Quantum sensors leverage the quantum states of defects in solid materials to detect minute environmental changes with extraordinary precision. Traditionally, diamond with its robust three-dimensional lattice has been the gold standard, protecting sensor defects against environmental noise due to its rigidity and structural perfection. Within this lattice, missing carbon atoms — known as atomic vacancies — act as quantum sensors, their electronic spins manipulated through carefully tuned laser and microwave pulses. However, while diamond’s three-dimensionality provides high stability, it also imposes limitations. The sensor defects are embedded relatively deep within the lattice, increasing the distance to the object of measurement and subsequently weakening the interaction strength and overall sensitivity.

Enter hexagonal boron nitride, a layered two-dimensional material composed of atom-thin planes. Unlike diamond’s rigid three-dimensional framework, hBN’s planar structure permits the creation and positioning of spin defects with exquisite atomic precision within a single layer. This architectural advantage dramatically shortens the distance between the sensor and the target, amplifying the sensor’s ability to interact with and detect signals from its surroundings. Particularly promising are negatively charged boron vacancy defects, which can be optically addressed at room temperature — a significant asset for practical applications where maintaining cryogenic conditions is challenging.

But proximity alone does not guarantee optimal sensor performance. The internal dynamics of these defects — their “quantum clock,” as it were — plays an equally crucial role. When these defects are excited by a laser pulse, electrons are promoted to higher energy states. For the sensor to reset and prepare for the next measurement rapidly, these excited electrons must relax back to their ground state efficiently. However, researchers found that electrons do not return directly; instead, they transiently occupy a peculiar metastable intermediate state, akin to a temporary holding area or “waiting room.” The duration of this intermediate state ultimately constrains the speed of measurement cycles and, by extension, the sensor’s temporal resolution and accuracy.

Until now, the temporal characteristics of this intermediate state were largely theoretical, inferred from simulations rather than direct observation. The JMU team’s breakthrough lies in their successful direct measurement of this elusive lifetime. By employing precisely timed laser pulses functioning like stroboscopic flashes, the researchers captured snapshots of electron relaxation dynamics within hBN. Their measurements established that, at room temperature, electrons remain in this metastable intermediate state for exactly 24 nanoseconds. Remarkably, cooling the material to the temperature of liquid helium nearly doubles this duration, highlighting the strong temperature dependence of relaxation dynamics in two-dimensional quantum systems.

Understanding this intrinsic “waiting time” translates into tangible improvements in sensor design and operation. The lifetime of the intermediate state informs the optimal timing between the excitation of the defect and subsequent quantum state manipulation through microwave pulses. The Würzburg team demonstrated that introducing a deliberate delay of approximately 150 nanoseconds after optical excitation dramatically enhances the coherent control of the electron spins by ensuring the intermediate state is fully vacated. This optimized timing prevents partial occupation of the intermediate state during quantum manipulation, thereby maximizing the number of spins ready for measurement in the ground state.

The practical outcomes of this temporal tailoring are compelling. The researchers reported a nearly 26% increase in the contrast of measurement signals — a direct reflection of the sensor’s ability to distinguish between different quantum states. Correspondingly, this translates to an 11% enhancement in the overall sensitivity of the quantum sensor. Such improvements are statistically significant, as sensitivity scales with the number of coherently addressed spins within the ensemble. By effectively “clearing the holding room,” the researchers have amplified both the signal strength and the reliability of the measurements, essential for real-world deployment of quantum sensor technologies.

This pioneering research is poised to catalyze the next generation of quantum sensors based on two-dimensional materials. By furnishing concrete experimental data on relaxation dynamics, it paves the way for the development of intricate measurement protocols tailored to the unique physics of hBN and similar materials. Furthermore, the ability to engineer timing at the quantum scale opens new possibilities for combining diverse two-dimensional materials into heterostructures with customized properties, potentially unlocking functionalities inaccessible in bulk or three-dimensional systems.

Nonetheless, challenges remain on the road ahead. The magnetic environment surrounding defects in hBN is inherently more complex than in diamond due to the high presence of magnetic isotopes in boron and nitrogen atoms. These nuclear spins act as sources of decoherence, shortening the quantum coherence times and potentially limiting sensor performance. Future investigations must focus on mitigating these decoherence channels — perhaps via isotopic engineering, material purification, or dynamic decoupling techniques — to fully harness the potential of two-dimensional quantum sensors.

The deep insights gained from this study underscore the indispensable symbiosis of experiment and theory in advancing quantum technologies. They highlight how meticulous temporal control, grounded in detailed knowledge of microscopic quantum processes, can translate into macroscopic enhancements in sensor capabilities. As quantum sensing moves from laboratory curiosities to practical tools for precision measurement, these findings will resonate through applications spanning navigation, medical diagnostics, environmental monitoring, and beyond.

The Würzburg team’s work exemplifies the transformative power of low-dimensional materials in quantum science. By peeling down the atomic layers to a single two-dimensional sheet, they have not only revealed fundamental quantum mechanisms but also charted a clear path towards devices that can measure the world with unprecedented speed and accuracy. With electron metastability characterized in exquisite detail and control protocols refined accordingly, quantum sensors based on hBN stand on the cusp of a new era, ready to deliver on their promise of revolutionizing the way we perceive and interact with the quantum world.

Subject of Research: Quantum sensor dynamics in two-dimensional hexagonal boron nitride.

Article Title: Intermediate excited state relaxation dynamics of boron vacancy spin defects in hexagonal boron nitride.

News Publication Date: 25-Feb-2026

Web References: 10.1126/sciadv.aea0109

Keywords

Quantum sensors, hexagonal boron nitride, boron vacancy defects, metastable intermediate state, spin defects, quantum coherence, two-dimensional materials, relaxation dynamics, quantum control, atomic sensors, coherent control, quantum technology.

Chiral halide perovskites have been at the forefront of materials science research due to their unique ability to control not only charge and light but also the spin orientation of electrons at room temperature. This peculiar trait is attributed to the CISS effect, which allows these materials to preferentially filter electrons based on their spin polarization—a fundamental quantum property that can encode information beyond traditional charge-based electronics. Leveraging this effect promises highly efficient, low-energy spintronic devices that could dramatically enhance information storage and transmission.

Yet, despite widespread interest, direct visualization and detailed understanding of the CISS effect at the microscopic scale have eluded researchers until now. Conventional experimental methodologies, while capable of detecting spin selectivity, fall short in capturing the spatial heterogeneity and local strength of the effect across material surfaces. This limitation impedes fine-tuning material properties for device applications, as microscopic inhomogeneities can critically affect performance and reliability.

To overcome these challenges, scientists collaborated across institutions—including the Ningbo Institute of Materials Technology and Engineering under the Chinese Academy of Sciences, the Hong Kong University of Science and Technology, and the U.S. National Renewable Energy Laboratory—to engineer a customized Kelvin probe force microscopy (KPFM) system. This advanced technique enabled them to perform high-resolution scans on chiral perovskite thin films under varying magnetic configurations, yielding detailed “spin maps” that quantify both the magnitude and uniformity of the CISS effect on the nanoscale.

The KPFM approach exploits subtle variations in surface potential modulated by spin orientations to construct spatially resolved images of spin polarization. Through sequential imaging while switching magnetic fields, the research team could discern how spin-dependent charge distribution evolves locally within chiral perovskite matrices. Such non-destructive, contactless probing represents a significant advance since it preserves the intrinsic material properties during measurement, permitting accurate characterization relevant to practical device conditions.

Beyond simply mapping spin behavior within the chiral films, the researchers uncovered the presence of spin–Schottky junctions at interfaces where chiral perovskites contact metal electrodes. These junctions exhibit spin-dependent energy barriers that dictate electron injection dynamics—crucial insights that illuminate how spin currents are modulated when moving across material boundaries. Understanding these interface phenomena is vital for engineering efficient spintronic devices, as interfacial spin filtering and scattering substantially influence overall device performance.

Further investigation revealed that multiple factors modulate the spin-selective efficiency of chiral perovskites. Key parameters include the nature of chiral cations incorporated into the lattice, thin film thickness, as well as synthesis and processing conditions. These factors collectively shape the spin orbit coupling and chiral asymmetry within the material, thereby tuning the strength of the CISS effect. Notably, the researchers observed marked nanoscale variations—spatial inhomogeneities in spin polarization—which could limit achievable device uniformity and call for more precise material engineering.

This pioneering work not only establishes a robust, quantitative platform for interrogating spin dynamics in chiral perovskites but also provides an essential blueprint to rationally design materials with enhanced spintronic functionality. By physically visualizing how spin selectivity manifests on the nanoscale, the study bridges the gap between fundamental quantum spin phenomena and scalable device architectures, fostering the development of next-generation, energy-efficient computing technologies.

Researchers emphasize that chiral perovskites, with their versatile optoelectronic and spin-dependent properties, occupy a unique position in the material landscape, capable of integrating light manipulation and spin control within a single system operable at ambient conditions. This dual capability opens exciting possibilities for multifunctional devices that merge photonics, electronics, and spintronics in coherent architectures.

Moreover, the experimental advances demonstrated through custom KPFM measurements stand to inspire new investigative approaches probing spin phenomena in a variety of chiral and low-dimensional materials. As the quest for spin-based information processing evolves, techniques able to resolve spin textures and dynamics in real space and real time will become indispensable tools for scientific discovery and technological innovation.

Ultimately, the insights garnered from this study provide a foundational step toward harnessing the power of spin polarization for transformative applications in quantum information science, memory devices, and neuromorphic circuits. By unveiling the nanoscale intricacies of spin selectivity and interface behavior, the research paves the way for the deliberate manipulation of electron spin with precision—an advancement expected to fuel the next wave of breakthroughs in material science and device engineering.

This cutting-edge research, published in the National Science Review, underscores the critical importance of interdisciplinary collaboration and technological innovation in realizing the full potential of chiral perovskites as versatile, high-impact materials for the future of spintronic and optoelectronic technologies.

Subject of Research: Nanoscale investigation of chiral-induced spin selectivity (CISS) effect in chiral halide perovskite thin films.

Article Title: Scientists map how chiral perovskites control electron spin.

News Publication Date: Not specified in source material.

Web References: http://dx.doi.org/10.1093/nsr/nwaf295

References: Published in National Science Review.

Image Credits: ©Science China Press

Keywords

Chiral halide perovskites, chiral-induced spin selectivity (CISS), Kelvin probe force microscopy (KPFM), spintronics, spin–Schottky junctions, electron spin, nanoscale spin mapping, quantum computing, optoelectronics, spin-polarized currents, material interfaces, neuromorphic computing.

Spintronics relies fundamentally on the intrinsic angular momentum—or spin—of electrons, promising a paradigm shift in computing and data storage technologies by transcending the limitations imposed by conventional charge-based electronics. Central to advancing this field is the development of materials that can robustly and selectively filter electron spins. The Korea-Seoul research team has addressed this by engineering chiral magnetic nanohelices whose handedness can be precisely programmed, thereby controlling the directional flow of electron spins with unprecedented efficiency.

The crux of this breakthrough lies in the successful fabrication of three-dimensional inorganic nanohelices exhibiting well-defined chirality—right- or left-handed twists—through an electrochemical growth process meticulously guided by trace amounts of chiral organic molecules. This subtle addition acts as a molecular director during metal ion reduction, steering the crystallization to form helices with the desired helicity. The ability to dictate handedness at such a fine scale in inorganic materials is an extraordinary feat given the synthesis challenges traditionally associated with chirality control in metal nanostructures.

Experimental characterization confirmed that these chiral nanohelices achieve spin polarization levels exceeding 80%, a metric reflecting the degree to which electron spin orientation can be sorted or filtered by the material. Crucially, this high spin selectivity is achieved solely through the intertwined effects of the nanohelices’ geometry and ferromagnetism, without relying on complex magnetic circuits or cryogenic environments. This represents a significant practical advance, as it allows spin-based effects to manifest at ambient temperatures with scalable fabrication methods.

Professor Young Keun Kim from Korea University, co-corresponding author of the study, emphasized the uniqueness of this approach: “Our method combines structural chirality and intrinsic ferromagnetism in a way that enables efficient spin filtering simply through nanohelix design. This geometric and magnetic synergy provides a new framework for engineering electron spin behavior without the typical technological overhead.”

Underlying the spin transport phenomenon is the concept of magnetization within the nanohelices. The inherent ferromagnetic ordering aligns electron spins over considerable distances, maintained by strong exchange energy interactions. This magnetization facilitates long-range spin coherence that remains stable regardless of the orientation between the chiral axis of the helix and the spin injection direction, a behavior absent in analogous non-magnetic nanoscale helices. This observation marks the first empirical demonstration of asymmetric spin transport in relatively large-scale chiral inorganic structures.

To rigorously verify the chirality of the nanohelices, the team developed an innovative electromotive force (emf)-based measurement technique. By subjecting the helices to rotating magnetic fields, the researchers detected opposite emf signals corresponding to left- and right-handed helices. This allowed them to quantify chirality even in materials with weak light-matter interaction, overcoming a persistent hurdle in nanoscale chirality evaluation. Such a methodology provides a powerful tool for future studies targeting chiral inorganic nanomaterials.

The technological implications of this research extend beyond fundamental science. The researchers demonstrated a prototype solid-state device based on their chiral nanohelices, successfully exhibiting spin-dependent conduction signals. This proof of concept illustrates the potential for integrating these materials into practical spintronic elements that leverage chirality to control spin currents without external magnetic fields or cryogenic cooling, thereby streamlining device architectures.

Professor Ki Tae Nam of Seoul National University, also a co-corresponding author, highlighted the broader significance of the work: “Chirality is a foundational principle in organic chemistry and biology, often dictating molecular function. Our success in programming inorganic chiral structures at the nanoscale represents a materials chemistry breakthrough that could transform spintronic device engineering.”

Besides enabling directional spin transport, the technique affords versatile control over nanostructure morphology. By adjusting the electrochemical conditions and chiral molecule concentrations, researchers can modulate not only the helicity but also the number of strands in the nanohelices, enabling access to double or multiple helical configurations. This tunability unlocks a rich design space where geometric and magnetic parameters can be jointly optimized for targeted spintronic functionalities.

Looking forward, this research sets a foundational platform for the emerging field of chiral spintronics. The convergence of geometry, magnetism, and electron transport within scalable inorganic nanoarchitectures promises a pathway to robust, energy-efficient spin devices suitable for integration into existing semiconductor technologies. The work points toward new possibilities in data storage, logic operations, and quantum information processing where spin-selective control is paramount.

In summary, the Korea University and Seoul National University collaboration has charted a new direction in nanoscale magnetism and spin transport by delivering chiral ferromagnetic nanohelices capable of spin polarization surpassing 80% under ambient conditions. Their elegant electrochemical synthesis guided by chiral molecules circumvents prior limitations in inorganic chirality control, enabling practical exploitation of geometric and magnetic effects to manipulate electron spin. This breakthrough paves the way for scalable, room-temperature spintronic devices that harness structural design principles to channel electron behavior in fundamentally novel ways.

Subject of Research: Spin-selective electron transport through chiral ferromagnetic nanohelices

Article Title: Spin-selective transport through chiral ferromagnetic nanohelices

News Publication Date: 4-Sep-2025

Web References:
10.1126/science.adx5963

Image Credits: Korea University and Seoul National University

Keywords

Spintronics, chirality, ferromagnetism, nanohelices, spin polarization, electron spin control, chiral magnetic materials, electrochemical synthesis, spin filtering, nanoscale magnetism, spin transport, room-temperature spintronics

Traditional electronic devices primarily manipulate the charge of electrons sailing through silicon-based semiconductors to encode and process information. However, as the demand for faster and more power-conscious computation escalates globally, this methodology confronts serious energy consumption and miniaturization limitations. Spintronics offers a tantalizing alternative by harnessing the intrinsic angular momentum—or spin—of electrons, which manifests as binary states labeled “up” or “down.” Encoding information in spin states can drastically reduce energy use because it potentially eliminates the need for electron movement, thereby enabling devices with smaller footprints and lower heat dissipation.

The chief hurdle in advancing spintronics lies in maintaining spin coherence; electron spins tend to relax swiftly due to interactions and collisions with atoms within a material. This scattering-induced decay leads to rapid loss of stored information, stalling development efforts for reliable spin-based technologies. The Rice University study introduces an innovative solution by bending 2D materials to exploit internal electric fields generated from strain gradients, a process known as flexoelectric polarization. When a sheet is creased or bent, the top layer experiences tensile strain while the bottom is compressed, causing a separation of charges that culminates in intricate internal fields influencing electron behavior.

These internal electric fields produced by mechanical deformation alter the spin-orbit interaction within the material, effectively splitting spin-up and spin-down electrons into different momentum spaces, resulting in the distinctive persistent spin helix state. Unlike conventional materials where electron spin direction shifts with momentum changes, in a PSH, spins maintain alignment despite scattering events. The researchers demonstrated this effect in MoTe₂, where the bending-induced flexoelectricity manages to stabilize the spin texture, dramatically extending its lifetime and coherence length.

A particularly striking aspect of this discovery is the remarkably short spin-precession length achieved—approximately 1 nanometer—the shortest reported for PSH systems to date. Spin-precession length refers to the distance over which an electron spin flips orientation. The extremely compact scale suggests that future spintronics devices leveraging these mechanically engineered wrinkles could be scaled down to dimensions previously considered unattainable. Such miniaturization harbors immense potential for integrating high-density spintronic components onto chips, advancing both speed and energy efficiency far beyond existing CMOS technology.

The formation of PSH states via mechanical creasing is inherently tied to the geometry and curvature of 2D materials. Wrinkles and hairpin-like folds, commonly observed in these ultrathin sheets, create regions of intense curvature that amplify the flexoelectric effect. These morphological features naturally induce substantial internal electric fields capable of modulating spin polarization profoundly. The Rice group’s insight that these nanoscale “mechanical pinches” inherently facilitate persistent spin states opens a new paradigm for designing novel materials and devices without relying on complex chemical doping or external fields.

What makes this approach particularly elegant is the convergence of macroscopic mechanical deformation with quantum relativistic physics governing electron spins. The flexoelectric-induced spin textures arise from an intricate interplay between elasticity and the spin-orbit coupling phenomena, bridging previously disconnected realms of physics. According to Sunny Gupta, a lead postdoctoral researcher on the study, such a union challenges conventional thinking since quantum coherence phenomena rarely align with bulk mechanical properties, making this discovery both conceptually profound and technologically transformative.

Beyond the immediate implications for spintronics, this research advances a versatile strategy for engineering exotic quantum field profiles in 2D materials. Precise control over curvature and strain gradients enables the tailoring of local electric fields with nano-scale resolution, thus fine-tuning spintronic functionalities. This capability could facilitate the creation of spin-based quantum devices with programmable properties, including highly sensitive sensors, non-volatile memory elements, and components for quantum information processing.

The study’s significance extends further considering the growing pressures on data centers and computing infrastructures worldwide, as their increasing electrical demand intensifies environmental concerns. Transitioning to spin-controlled electronics promises lower power dissipation and sustainable scaling, which are pivotal for the future of green technology. It also aligns with the quest for post-silicon computing architectures that overcome the physical and economic constraints hindering silicon transistor miniaturization.

Funded by multiple U.S. agencies, including the Office of Naval Research, Army Research Office, National Science Foundation, Department of Energy, and Department of Defense, the research benefits from a collaborative framework attuned to scientific innovation with practical impact. Boris Yakobson, the Karl F. Hasselmann Professor and corresponding author, emphasizes the simplicity and accessibility of the method: “A humble ‘mechanical pinch,’ which occurs easily in 2D materials, splits the spins and induces PSH texture.” This suggests widespread applicability across a variety of 2D materials and device architectures.

In summary, this discovery underscores the enormous potential embedded in the mechanical manipulation of ultra-thin materials to orchestrate quantum spin states robustly. By leveraging naturally occurring wrinkles and folds, researchers can now envision a future where computer processors and memory components operate on entirely new quantum mechanical principles, promising leaps in computational speed and energy efficiency. As the field of spintronics continues to mature, such innovative approaches will undoubtedly be critical to unlocking next-generation technologies that redefine the limits of electronics.

Subject of Research: The mechanical modulation of electron spin states in two-dimensional materials for spintronic applications.

Article Title: Mechanical crease in 2D materials — A platform for large spin splitting and persistent spin helix

News Publication Date: 21-Aug-2025

Web References:
https://news.rice.edu/
https://www.sciencedirect.com/science/article/pii/S2590238525004217?via%3Dihub
http://dx.doi.org/10.1016/j.matt.2025.102378

References:
Gupta, S., Yakobson, B.I., et al. “Mechanical crease in 2D materials — A platform for large spin splitting and persistent spin helix.” Matter, 19-Aug-2025. DOI: 10.1016/j.matt.2025.102378

Image Credits: Photo by Jorge Vidal/Rice University

Keywords

Spintronics, Engineering, Materials science, Two dimensional materials, Spin polarization, Molecular dynamics

The exploration of alternative methods for spin selection has intensified over the past decade, with one promising avenue being the use of chiral molecules—those that cannot be superimposed onto their mirror images. Helices, which are common structures in these molecules, have shown remarkable potential. Research has indicated the capability of inducing a spin polarization of around 60 to 70 percent in currents passing through chiral molecules, a level comparable to that achieved with conventional ferromagnetic materials. Nevertheless, the intricacies involved in this process have kept it mired in scientific discussion and ongoing investigation.

Recent breakthroughs from the researchers at Johannes Gutenberg University Mainz (JGU) have illuminated the concept of chiral-induced spin selectivity (CISS) effect. This pivotal research highlights the interaction between spin currents and chiral molecules in a novel hybrid system. According to Professor Angela Wittmann of the JGU Institute of Physics, their team employed spintronic techniques in a way that deviated from traditional methods. Rather than passing the charge current directly through the chiral molecules, they developed a hybrid arrangement combining a thin gold film topped with chiral molecules, allowing for an innovative approach to the study of spin-to-charge conversion.

In pure gold films, a mere three percent of the spin current is typically transformed into a charge current, unaffected by the orientation of electron spins. However, the introduction of chiral molecules on the surface of this gold film transforms the dynamics drastically. When right-handed molecules are present, electrons with spin-up transition to charge current much more effectively than their spin-down counterparts. This interaction is reversed with left-handed chiral molecules, demonstrating that chirality plays a crucial role in the conversion efficiency of spin to charge.

The implications of these advancements extend beyond the realm of theoretical research; they tap into potential applications in future technology. The ability to selectively convert spin currents to charge currents, depending on molecular chirality, may facilitate the development of more efficient data storage devices and other technological advancements. These findings signify a step forward in understanding the fundamental interactions between spin and charge, emphasizing the pivotal role of molecular structure in such processes.

This investigation into the CISS effect also reveals an inherent vectorial characteristic. The efficiency of spin-to-charge conversion is contingent upon the alignment between the spin direction and the helix orientation of the chiral molecule. When aligned, this phenomenon occurs optimally, while misalignment negates the effect. Thus, the study not only underscores a key principle in spintronics but also opens avenues for designing devices that exploit these chiral interactions for practical applications.

The promise of this research lies in its capacity to bridge gaps between theoretical and practical realms in spintronics. By shedding light on the fundamental interplay between electron spin and chiral structures, scientists are approaching a deeper comprehension of how to harness these properties in innovative ways. The work conducted by Professor Wittmann’s team at the JGU serves as a cornerstone for future explorations and technological implementations, highlighting the significance of chiral molecules in spin phenomena.

As this field evolves, it holds the potential to redefine our understanding of electronics and data storage, ultimately leading to faster, more efficient devices. Spintronics, powered by chirality, could lead to a technological renaissance where electronic devices become increasingly sophisticated, energy-efficient, and compact. The quest for efficient spin selectivity may well be the key to unlocking new frontiers in material science and engineering innovations.

In conclusion, the groundbreaking research at Johannes Gutenberg University Mainz establishes a crucial contribution to the ongoing discourse surrounding spin selectivity and chiral molecular effects. As the scientific community continues to investigate and exploit these findings, we may very well be on the cusp of a significant leap forward in the abilities of electronic devices.

Subject of Research: Chiral-induced spin selectivity in hybrid systems
Article Title: Chiral-induced unidirectional spin-to-charge conversion
News Publication Date: 1-Jan-2025
Web References: Science Advances DOI
References: Not provided
Image Credits: Angela Wittmann

Keywords

Spintronics, chiral molecules, spin selectivity, electron spin, data storage, hybrid systems, charge current, chirality, gold thin films, unidirectional conversion, magnetic moment, quantum mechanics.