In the relentless pursuit of technological advancement, managing heat flow remains a formidable obstacle, especially within the realms of electronics and photonics. Heat dissipation not only curtails the operational efficiency of devices but also imposes stringent limits on their miniaturization potential. This challenge is particularly critical as modern technologies trend toward smaller, faster, and more powerful systems that generate significant thermal loads which traditional cooling methods struggle to handle effectively. In this context, two-dimensional (2D) materials, composed of atomically thin layers, have emerged as exciting candidates for next-generation device architectures due to their exceptional electrical and mechanical characteristics. Yet, despite their promise, understanding and manipulating their thermal characteristics has remained an elusive goal.
A groundbreaking exploration led by an international consortium of scientists from the Institut Català de Nanociència i Nanotecnologia (ICN2), Autonomous University of Barcelona (UAB), Eindhoven University of Technology (TU/e), and McGill University has unveiled an unprecedented mode of heat transport within ultrathin 2D semiconductors. Focusing primarily on molybdenum disulfide (MoS₂) and molybdenum diselenide (MoSe₂), their study reveals a novel regime termed “hydro-thermoelastic transport,” distinguished by a drastic hindrance in thermal diffusion. These insights, recently published in Nature Physics, provide an entirely new perspective on nanoscale heat conduction with profound implications for the future of thermal management technologies in miniaturized devices.
Traditionally, thermal energy propagates via diffusive processes, gradually flowing from hotter areas to cooler ones in a manner well-described by Fourier’s law. However, the research team’s meticulous experiments challenge this classical model, exposing a much more intricate landscape of heat transport phenomena in ultrathin semiconductors. Key to this discovery is the observation of phonon hydrodynamics, an exotic state wherein heat carriers known as phonons move collectively, exhibiting fluid-like, viscous behaviors that starkly contrast with independent particle diffusion. This emergent hydrodynamic regime reshapes our foundational understanding of thermal conduction at the nanoscale.
Concurrently, the study identifies compelling interactions between thermal transport and the mechanical properties of these ultrathin materials. As heat induces localized expansions and contractions within the atomic lattice, mechanical stresses arise that dynamically modify the propagation pathways of heat. This coupling between thermoelastic deformations and phononic hydrodynamics generates feedback loops that were previously unobserved in 2D semiconductor systems. Such thermoelastic effects not only impede heat diffusion but can actively redirect heat flow, altering the classical paradigm of thermal gradients.
Remarkably, these complex interactions result in strikingly slow heat propagation rates—thermal diffusivities are suppressed by as much as an order of magnitude compared to conventional predictions. Employing advanced optothermal microscopy techniques boasting nanometer spatial resolution and real-time tracking, the researchers could visualize these unexpected thermal dynamics with unparalleled clarity. This breakthrough was underscored by Professor F. Xavier Alvarez of UAB, who highlighted the novel mechanical stress contributions that constrain thermal fluxes in these materials, reshaping the distribution of heat and, in some cases, even blocking its flow.
Even more astonishing is the discovery that under specific conditions, heat can flow counterintuitively “backwards,” migrating from colder to hotter regions. Such heat fluxes opposing traditional gradients contradict established thermodynamic intuition and signify a paradigm shift in how thermal energy can be controlled intrinsically. Leading author Professor Klaas-Jan Tielrooij from ICN2 and TU/e emphasized that this capability to modulate heat internally—without external structural modifications—ushers in new avenues for dynamic thermal regulation, with potentially revolutionary applications across the semiconductor and photonics industries.
This phenomenon of “heat retention” in the heated zones is attributed to the synergistic interactions between phonon hydrodynamics and hydro-thermoelastic effects, effectively creating thermal bottlenecks that sustain localized energy reservoirs longer than expected. By engineering the interplay of these mechanisms, it may become feasible to design devices that either confine heat deliberately or channel it with exquisite precision, overcoming longstanding hurdles in thermal management. This capability is particularly advantageous for 2D semiconductors poised to revolutionize transistor technology and beyond, where managing nanoscale heat dissipation is critical for device reliability and performance.
Beyond practical device implications, this research significantly advances fundamental physics by illuminating how heat behaves in reduced dimensions under coupled mechanical and thermal perturbations at room temperature. Whereas prior studies of phonon hydrodynamics were often confined to cryogenic conditions or bulk crystals, demonstrating these effects at ambient temperatures in ultrathin materials marks a watershed moment. It suggests that 2D semiconductors are versatile platforms for studying complex non-equilibrium thermodynamics, with broad relevance across condensed matter physics, materials science, and applied nanotechnology.
The methodological innovations employed in this study are as remarkable as the scientific findings themselves. The team leveraged a cutting-edge optothermal technique capable of simultaneous nanoscale spatial resolution and real-time temporal tracking of heat propagation. This capacity allowed direct observation of the subtle mechanical deformations and viscous heat flows that would be impossible to detect by conventional means. Consequently, the experimental framework paves the way for future investigations into customizable thermal properties via strain engineering, substrate interaction tuning, and device geometry design.
Looking forward, these findings open up a tantalizing vista of possibilities for next-generation electronics and photonics. The ability to suppress or selectively redirect heat within materials without resorting to complex external heat sinks or structural alterations could drastically improve energy efficiency and thermal stability. Moreover, this intrinsic control over heat flow could be harnessed to develop novel thermoelectric devices that convert waste heat into usable electrical energy more effectively, contributing to sustainable energy solutions.
Such advances could redefine thermal management protocols in integrated circuits, allowing for denser packing of components without overheating risks. In photonics, controlling heat with unprecedented finesse can enhance laser performance, sensor sensitivity, and optical modulator stability. The hydro-thermoelastic transport regime thus represents not just a scientific curiosity but a transformative framework with the potential to impact a wide spectrum of technologies reliant on precise thermal control at the nanoscale.
In summation, the collaborative research by ICN2, UAB, TU/e, and McGill Universities fundamentally disrupts conventional thermal transport models in two-dimensional semiconductors. Through the discovery of hydro-thermoelastic transport and its profound effects on phonon behavior and mechanical deformation, they provide a compelling narrative on heat flow’s newfound fluidity and controllability. As device miniaturization accelerates and thermal constraints become increasingly critical, these insights equip scientists and engineers with powerful new tools to innovate and overcome one of the most pervasive challenges in modern technology.
Subject of Research: Not applicable
Article Title: Controllable hydro-thermoelastic heat transport in ultrathin semiconductors at room temperature
News Publication Date: 15-May-2026
Web References:
https://www.nature.com/articles/s41567-026-03297-1
References:
Varghese, S., Alvarez, F. X., Tielrooij, K.-J., et al. (2026). Controllable hydro-thermoelastic heat transport in ultrathin semiconductors at room temperature. Nature Physics. DOI: 10.1038/s41567-026-03297-1
Image Credits: Not specified
Keywords
Heat transport, phonon hydrodynamics, hydro-thermoelastic transport, 2D semiconductors, molybdenum disulfide, molybdenum diselenide, thermal diffusivity, nanoscale thermal management, thermoelastic deformation, optothermal techniques, phonons, thermal conductivity modulation
