Physics colloquium-“Strange Things Happen When Nanomaterials are Driven Far From Equilibrium”

Jonathan Bird

SUNY Buffalo

Abstract: The past two decades have witnessed an explosion of interest in functional nanomaterials, whose rich physical properties reflect their reduced dimensionality, the importance of spin- and charge-based interactions, and the existence of complex correlated phases. The application of these materials in various technologies – that span from clean energy to quantum computing – is premised upon a deep understanding of their physical properties. Specifically, the behavior that they exhibit when driven out of equilibrium, by strong electric and/or optical fields, can be crucial to many of these applications.

In my presentation, I summarize some of the experiments that we have performed in recent years to investigate the behavior exhibited by a variety of different nanomaterials that are driven electrically far from equilibrium. In many situations, this driving gives rise to fundamentally new behavior, not associated with the material in its near-equilibrium state. Just a few such examples include the emergence of robust one-dimensional transport in narrow semiconductor channels subject to strong phonon emission [1]; negative-mass amplification in the narrow conduction-band states of transition-metal trichalcogenide nanowires [2]; Landau-Zener tunneling across the minibands of (graphene/h-BN) van der Waals heterostructures [3]; and dynamic resistive-switching phenomena associated with charge-density wave evolution in layered transition-metal dichalcogenides [4,5]. I will provide an overview of some of these phenomena in my presentation, focusing on the use of time-resolved, transient, electrical measurements to probe the nonequilibrium dynamics with sub-nanosecond resolution.

References

1. Lee, J. E. Han, S. Xiao, J. Song, J. L. Reno, and J. P. Bird, Nat. Nanotechnol. 9, 101 (2014).
2. Randle, …, J. P. Bird, Nat. Materials, under review (2025).
3. Nathawat, …, J. P. Bird, Nat. Communs. 14, 1507 (2023).
4. A Mohammadzadeh, …, J. P. Bird, Appl. Phys. Lett. 118, 093102 (2021).
5. Yin, …, J. P. Bird, Adv. Phys. Res. 3, 2400033 (2024).

Biosketch: Jonathan Bird joined the UB Department of Electrical Engineering as full professor in 2004. He currently serves as chair of that department and as director of the UB Center for Advanced Semiconductor Technologies. Jonathan obtained his BSc (First-Class Honors) and PhD degrees in physics from the University of Sussex (UK) in 1986 and 1990, respectively. He was JSPS Visiting Fellow at the University of Tsukuba (Japan, 1991 – 1992) and a member of the Frontier Research Program of the Institute of Physical and Chemical Research (RIKEN, Japan, 1992 – 1997). Professor Bird’s research is in the area of nanoelectronics; he is currently supported by the Coherent/II-VI Foundation, the US Air Force Office of Scientific Research and the National Science Foundation.

All lectures held in CTLM102 unless otherwise specified

Pre-seminar snacks will be offered in CoorsTek 140 from 3:30pm-4:00pm.