Photon-driven electron excitation is a foundational mechanism underpinning the interaction between light and matter in quantum materials, including van der Waals materials, Dirac and Weyl semi-metals, topological insulators and other emergent phases. These enable next-generation optoelectronic, energy conversion and quantum information technologies. However, translating this mechanistic understanding into an engineering implementation is hindered by excitation efficiency, environmental stability and scalable fabrication. In this Review, we provide a mechanistic perspective on key photon-driven electron-excitation processes based on energy flow pathways, including electron–hole generation in semiconductors, high-mobility electron transport in semi-metals, photoemission from metals and low-dimensional materials, and light-induced thermoelectric effects. We examine engineering strategies to enhance the efficiency of these processes, including interface control, material selection and compatible integration. By bridging fundamental mechanisms with device-level metrics, this Review offers a unified framework and practical roadmap for advancing scalable, multifunctional optoelectronic devices that integrate sensing, data storage and computation.

Dong, X., Huo, J., Xiong, Y. et al. Photon-driven electron excitations in quantum materials.
Nat Rev Electr Eng (2026). https://doi.org/10.1038/s44287-026-00314-6

The essence of the cluster system lies in its ability to grow materials with atomic precision, a process that had previously required multiple separate steps, often involving the transfer of samples between different instruments. Traditionally, researchers faced the arduous task of moving samples out of one apparatus to send them to another for analysis, which inherently came with risks of contamination and delays. By contrast, the NRL’s innovation consolidates this entire process under one roof, dramatically streamlining the research workflow.

Dr. Connie Li, a leading research scientist at NRL, expressed her enthusiasm about the innovative capabilities of the cluster system, invoking a sense of excitement akin to “Christmas came early.” The system empowers researchers to not only grow materials one atomic layer at a time but also to immediately examine their structures and electronic properties in situ. This capability is pivotal for understanding the intricate behaviors of quantum materials, shedding light on their applications in future technologies.

Central to the functionality of the cluster system is its integration of various growth and characterization techniques. All these methods coalesce around a central interface chamber, where a robotic transfer arm efficiently navigates samples between different chambers while maintaining an ultra-high vacuum environment. This seamless transition allows for uninterrupted experimentation, maximizing the potential for real-time observation and analysis.

The cluster system employs molecular beam epitaxy, a sophisticated technique that enables the precise deposition of materials at the atomic scale. This method is vital for the creation of new materials with unique properties, as it allows scientists to construct thin films of materials one atomic layer at a time, continuously monitoring the growth process. Coalescing growth with characterization means that researchers can observe modifications at the atomic level as they occur, enabling immediate adjustments and refinements to the growth process.

Additionally, the system incorporates advanced imaging and spectroscopy techniques to facilitate comprehensive analysis of the materials being developed. Tools such as scanning tunneling microscopy (STM) offer the capability to visualize individual atoms, while angle-resolved photoemission spectroscopy (ARPES) is employed to map out the electronic band structures of these new materials. These powerful techniques provide unprecedented insight into the electronic properties and structural integrity of the synthesized materials.

The transition from traditional research methodologies to the cluster system marks a paradigm shift in how materials are studied and understood. Previously, the need to transport materials for analysis would often introduce uncertainties and risks, which could lead to inconsistent results. The ability to monitor and refine the material growth process in real time, without the interruption and exposure to potentially contaminative environments, enhances the integrity and reliability of the research.

Focused on the realm of quantum materials, the research being conducted within the cluster system is most relevant to the exploration of superconductors and topological insulators. Superconductors are materials that can conduct electricity with zero resistance, presenting exciting opportunities for energy-efficient technologies. Meanwhile, topological insulators, which only conduct electricity on their surfaces, hold promise for robust electronic applications, resilient even in the presence of defects.

As the need for advanced electronic devices grows, the importance of these materials cannot be overstated. NRL’s groundbreaking work with the cluster system is poised to contribute substantially to the future of Navy and Department of Defense technologies. Innovations in memory storage, advanced sensors, and efficient electronics could fundamentally alter the landscape of technology as we know it, opening doors to new applications previously thought to be unattainable.

Dr. Olaf van ‘t Erve, also a research scientist at NRL, echoed Dr. Li’s sentiments, highlighting the system’s capability to produce materials that transcend the limitations of current silicon-based technologies. As researchers probe deeper into the unique properties offered by quantum materials, the potential applications span a wide array of fields, each promising to enhance operational efficiencies and technological prowess.

The installation of the cluster system is now complete, and it has reached operational status. Researchers at NRL are optimistic that this tool will significantly accelerate discoveries in quantum materials, shortening the timeline from fundamental scientific exploration to practical applications. This advancement could pave the way for innovative solutions that bolster the capabilities of both the Fleet and the Nation.

In essence, the unveiling of this cluster system represents a transformative moment in material science, one that blends cutting-edge technology with groundbreaking research methodologies. NRL’s commitment to pushing the boundaries of science once again reaffirms its role as a leader in the exploration of advanced materials. As scientists embark on this new journey of discovery, the opportunities seem boundless.

The field of quantum materials is at a crossroads, with NRL firmly positioned at the forefront. As researchers delve into this vibrant domain, the outcomes of their efforts may well redefine our understanding of electronic materials and, ultimately, the technology we rely on in the years to come.

Subject of Research: Quantum Materials Synthesis and Characterization
Article Title: Accelerating Discovery: The U.S. Naval Research Laboratory’s Innovative Cluster System
News Publication Date: September 9, 2025
Web References: Not available
References: Not available
Image Credits: U.S. Navy photo by Sarah Peterson

Keywords

Quantum materials, Superconductors, Topological insulators, Electronics, Molecular beam epitaxy, Scanning tunneling microscopy, Angle-resolved photoemission spectroscopy.

Vacuum, often misconstrued as absolute emptiness, is in reality a dynamic arena dominated by transient virtual particles, particularly photons, whose spontaneous and ephemeral manifestations engender tangible impacts on physical systems. Optical cavities—microscopic spaces bounded by highly reflective mirrors—have been instrumental in concentrating these quantum vacuum fluctuations to manipulate matter at fundamental levels. However, conventional cavities amplify fluctuations symmetrically for both right- and left-handed circular polarizations, lacking the ability to bias one over the other in absence of intense external magnetic influence.

The Rice-led research team, spearheaded by the pioneering physicist Junichiro Kono, has devised an ingenious cavity architecture integrating lightly doped indium antimonide, a semiconductor renowned for its exceptional infrared detection qualities. The photonic-crystal cavity constructed with this material introduces an unprecedented degree of control over vacuum fields, enabling a pronounced chirality with drastically diminished magnetic field demands—reducing the intensity required by an order of magnitude compared to earlier efforts. This feat not only enhances the feasibility of practical deployment but also preserves the pristine properties of materials housed within the cavity.

Underpinning this experimental breakthrough lies an intricate fusion of theoretical modeling and numerical simulation. By combining classical electromagnetic field mapping with quantum density functional theory and cavity quantum electrodynamics frameworks, the team forged a multiscale hybrid model capable of accurately forecasting how target materials respond to engineered vacuum fields. This comprehensive approach overcomes the limitations of previous models, which often treated light and matter interactions in isolation or under oversimplified assumptions.

Graphene, a single atomic layer of carbon atoms arranged in a flawless hexagonal lattice, emerged as the prime candidate material to demonstrate the cavity’s transformative efficacy. When introduced into the chiral cavity environment, graphene’s electronic band structure undergoes a remarkable modification: the normally gapless Dirac cones open a band gap, inducing a novel topological insulating state. This quantum phase transition could have profound implications for quantum computing, where such topological materials may enable more robust, fault-tolerant qubits and pave paths toward scalable quantum architectures.

Achieving this level of vacuum-mediated material transformation without resorting to cumbersome external controls, such as enormous magnetic fields or extreme temperatures, heralds a paradigm shift in quantum materials engineering. Instead of applying direct stimuli, scientists can now manipulate matter’s intrinsic properties simply by tailoring the quantum vacuum environment surrounding the material—a concept Kono terms "reshaping vacuum." This approach could revolutionize device fabrication by reducing complexity and enhancing material stability.

The intricate design of the cavity was optimized through extensive, cutting-edge computational simulations led by Alessandro Alabastri and Stephen Sanders, which accurately tuned the photonic-crystal layers to sustain long-lived, uniform circularly polarized vacuum fields. By circumventing the laborious and resource-intensive trial-and-error fabrication process, this simulation-driven methodology not only expedited the cavity’s development but also afforded unparalleled design flexibility, enabling exploration across vast parameter spaces for optimal performance.

At the heart of the chiral cavity’s operation is the delicately balanced interplay of charge carriers in the indium antimonide semiconductor. Their exceptionally low effective mass allows modest magnetic fields to selectively suppress vacuum fluctuations propagating in one direction, while leaving the opposite polarization largely unaffected. This finely tuned suppression imbues the cavity with a handedness that translates directly into asymmetric quantum interactions with embedded materials—a long-sought-after goal in photonic engineering and quantum electrodynamics.

This breakthrough carries transformative potential beyond graphene, as the constructed theoretical framework and cavity platform can be readily extended to diverse materials. Exploring how various quantum materials interact within chiral vacuum fields can unlock a new arsenal of engineered quantum phases and functionalities, with applications spanning from next-generation photonic devices to novel sensors and quantum simulators.

The implications of manipulating quantum vacuum fluctuations extend deeply into condensed matter and quantum optics research, offering tools to probe fundamental symmetries and topologies of matter. As outlined by theorists involved in the study, the engineered band gap in graphene is a manifestation of the interaction between chiral photons and electronic states inside the cavity, opening avenues to precisely engineer Dirac physics phenomena with light in ways previously unattainable.

Instrumental financial backing from the U.S. Army Research Office, the Gordon and Betty Moore Foundation, the Robert A. Welch Foundation, and the National Science Foundation enabled the convergence of cutting-edge experimental and theoretical efforts. The successful synthesis of theory, simulation, and experiment serves as a blueprint for multidisciplinary collaboration integral to advancing quantum technology frontiers.

Rice University’s Smalley-Curl Institute, under the stewardship of Kono who holds the Karl F. Hasselmann Professorship, continues to be a beacon for quantum materials innovation. This latest discovery epitomizes how reimagining the seemingly empty vacuum as an active participant in quantum engineering can lead to practical routes for developing novel quantum devices and technologies with unprecedented control, efficiency, and scalability.

As this research garners attention across the scientific community, it ignites fresh enthusiasm to further harness chiral quantum vacuum fields, inspiring future explorations where manipulating the quantum vacuum itself becomes a versatile tool. The fusion of photonics, semiconductor physics, and quantum theory in this study illuminates a bold path forward in the quest to architect matter at its most fundamental quantum level.

Subject of Research: Terahertz chiral photonic-crystal cavities and quantum vacuum engineering in graphene

Article Title: Terahertz chiral photonic-crystal cavities for Dirac gap engineering in graphene

News Publication Date: June 17, 2025

Web References:

• https://www.nature.com/articles/s41467-025-60335-x
• https://news.rice.edu/

References:
Fuyang Tay, Stephen Sanders, Andrey Baydin, Zhigang Song, Davis Welakuh, Alessandro Alabastri, Vasil Rokaj, Ceren Dag, and Junichiro Kono. "Terahertz chiral photonic-crystal cavities for Dirac gap engineering in graphene." Nature Communications, 2025. DOI: 10.1038/s41467-025-60335-x

Image Credits: Rice University / Nature Communications

Keywords

Quantum fluctuations, quantum matter, quantum states, graphene, chirality, photonics, light-matter interactions, cavity quantum electrodynamics

Superfluorescence, a collective quantum phenomenon where groups of excited particles emit light in a coherent burst, shares kinship with other exotic quantum phases such as superconductivity and superfluidity. These phenomena arise when numerous quantum particles synchronize their behavior, collectively acting as a single coherent entity that transcends the limitations of individual particles. Typically confined to low-temperature regimes to avoid thermal disturbances, achieving such states at ambient conditions has long eluded scientists. Thermal noise, a formidable adversary, disrupts the delicate synchronization necessary for these macroscopic quantum phase transitions.

The research team, spearheaded by Kenan Gundogdu at North Carolina State University and comprising collaborators from Duke University, Boston University, and the Institut Polytechnique de Paris, has elucidated how certain hybrid perovskites overcome thermal noise to sustain these phase transitions. Central to their discovery is the role of polaronic quasiparticles—entities formed when electrons become strongly coupled to lattice distortions within the crystal structure. These large polarons act as insulating shields, protecting the quantum dipoles responsible for superfluorescence from thermal agitation.

A pivotal insight from this study is the observation of soliton formations—coherent, self-reinforcing wave packets—arising from the synchronization of polarons under laser excitation. Gundogdu analogizes the material’s atomic lattice to a taut fabric, with excitons represented as balls that deform this fabric locally. When these distortions order themselves collectively, forming solitons, the system exhibits a macroscopic quantum coherence capable of suppressing disruptive thermal fluctuations. Experiments directly captured the transition of polaron populations from incoherent, disordered phases to ordered, coherent soliton states, marking one of the first direct observations of macroscopic quantum state formation at elevated temperatures.

The soliton formation hinges on exceeding a critical density of excited polarons, beyond which the system spontaneously organizes into these coherent units. Through the work of Ph.D. student Mustafa Türe and postdoctoral researcher Melike Biliroglu, the team demonstrated both theoretically and experimentally that below this density threshold, polarons remain free and uncorrelated; above it, collective synchronization manifests as solitons. This transition—a hallmark of quantum phase phenomena—effectively creates a resilient macroscopic quantum entity in the presence of thermal noise.

Complementing the experimental findings, collaborators at Duke University and the Institut Polytechnique de Paris contributed sophisticated lattice dynamics simulations. These calculations illuminated how lattice oscillations, which ordinarily mediate thermal dephasing, are effectively dampened by soliton formation. The theoretical models confirm that exciton-lattice interactions intertwine electronic and structural degrees of freedom, fostering a new, entangled polaronic state that endures at high temperatures, thus facilitating superfluorescence.

This integrated approach combining high-resolution experimentation and rigorous theoretical modeling provides unprecedented clarity on the interplay between electron-lattice coupling and quantum coherence. Previously, the field grappled with gaps in understanding which material attributes reliably support high-temperature macroscopic quantum states. Now, the detailed phase transition map uncovered here offers blueprints for engineering novel quantum materials that maintain coherence without cryogenic cooling, dramatically expanding their applicability.

The implications for quantum technology are profound. Quantum communication, cryptography, sensing, and computation—fields currently constrained by the demanding infrastructure of ultra-low temperatures—stand to benefit immensely. By harnessing these soliton-mediated quantum states, future devices could operate under ambient conditions, simplifying design, reducing costs, and accelerating deployment. Franky So, co-author and NC State materials science distinguished professor, highlights that this breakthrough transforms theoretical possibilities into practical guidelines for next-generation quantum material innovation.

The experimental strategy involved exciting a lead-halide perovskite sample with ultrafast laser pulses, provoking large polaron formations. Subsequent optical measurements tracked intensity fluctuations in the macroscopic polarization, revealing the hallmark signs of superfluorescence emerging synchronously with polaron synchronization. These observations confirm that the transient excitonic recombination dynamics are intimately linked to the collective ordering of polarons into a coherent extended state.

Beyond opening pathways for room-temperature superconductivity and superfluidity analogs, this work also deepens fundamental physical understanding. It bridges transient nonequilibrium processes, like impulsively induced superfluorescence, with equilibrium thermodynamic phase transitions conventionally achieved via cooling. This unification hints at a general principle governing high-temperature macroscopic quantum phenomena across diverse material platforms, guiding future explorations in condensed matter physics.

This landmark study, supported by the U.S. Department of Energy Office of Science, exemplifies the power of interdisciplinary collaboration combining experimental physics, theoretical modeling, and materials engineering. The synergy among the involved institutions and international partners underscores the global nature of addressing complex quantum technological challenges. As the field advances, these insights lay a firm foundation upon which to build devices that unlock quantum functionalities previously thought accessible only under cryogenic conditions.

The discovery of soliton-driven superfluorescence in hybrid perovskites is more than a scientific milestone; it signals a paradigm shift in how materials can be designed and manipulated to support resilient macroscopic quantum states. By decoding the mechanisms that enable coherence amidst thermal noise, the research community can now embark on crafting tailored quantum materials optimized for ambient operation. This will likely accelerate the advent of practical quantum information technologies, bringing the quantum revolution closer to everyday reality.

Subject of Research: Not applicable

Article Title: Unconventional solitonic high-temperature superfluorescence from perovskites

News Publication Date: 28-May-2025

Web References: 10.1038/s41586-025-09030-x

References: Gundogdu et al., "Spontaneous Polaron Synchronization Leads to High-Temperature Perovskite Superfluorescence," Nature, May 28, 2025.

Keywords

Superfluorescence, hybrid perovskites, polaron synchronization, solitons, macroscopic quantum coherence, high-temperature quantum phenomena, exciton-lattice interactions, quantum phase transitions, room temperature quantum effects, condensed matter physics, quantum information technology, thermal noise suppression

Credit: John C. Thomas/Berkeley Lab