Lunch will be provided at 12:00pm, so please come early to eat mingle and eat lunch before the talk begins.
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Abstract: The re-invigorated field of electron hydrodynamics in quantum matter has recently garnered considerable scientific interest, both due to its technological promise of designing near
dissipation-less nanoelectronics, as well as its fundamental importance as an experimental probe of strong electron-electron interactions. Investigating the capacity to which observations of electron hydrodynamic flows can inform the nature of electron-electron interactions is particularly important and timely with the advent of spatially-resolved transport measurements which, having demonstrated the hallmark spatial signature of electron hydrodynamic channel flow, must now turn their attention to studying more spatially-complex geometries, enabling the observation of intricate fluid phenomena such as vortices. Recently we have explored the effects of crystal symmetry on electron fluid behaviors starting from the most general viscosity tensors in two and three dimensions, constrained only by crystal symmetry and thermodynamics. In our work we demonstrate the anomalous landscape for electron hydrodynamics in systems beyond graphene, highlighting that previously-thought exotic fluid phenomena can exist in both two-dimensional and anisotropic three-dimensional materials with or without breaking time-reversal symmetry. In this context, the first part of my talk will discuss our recent predictions of hydrodynamics beyond graphene1–5, especially the role of phonons in hydrodynamics in Weyl semimetals 4,6–10. We identify phonon-mediated electron-electron interactions, computed with techniques developed in the group that I will discuss in this talk, as critical in a microscopic understanding of hydrodynamics. The second part of my talk will introduce a new theoretical and computational transport framework from our group, the SpaRTaNS (Spatially Resolved Transport of Nonequilibrium Species) framework. I will discuss applications of this method in nonequilibrium electron and phonon transport11, and ideas on extending it to magnon transport in quantum matter. Finally, building on our recent work in magnetic Weyl semimetals, I will discuss possible approaches to understand and realize axion physics in condensed-matter systems12–14.
References and links:
SpaRTaNS: Link to Github https://narang-lab.github.io/spartans/
1. Varnavides, G., Jermyn, A. S., Anikeeva, P., Felser, C. & Narang, P. Electron hydrodynamics in
anisotropic materials. Nat. Commun. 11, 1–6 (2020).
2. Vool, U. et al. Imaging phonon-mediated hydrodynamic flow in WTe2. Nat. Phys. 17, 1216–1220
(2021).
3. Varnavides, G., Jermyn, A. S., Anikeeva, P. & Narang, P. Probing carrier interactions using electron
hydrodynamics. arXiv [cond-mat.mtrl-sci] (2022).
4. Varnavides, G., Wang, Y., Moll, P. J. W., Anikeeva, P. & Narang, P. Finite-size effects of electron
transport in PdCoO2. Phys. Rev. Mater. (2021) doi:10.1103/physrevmaterials.6.045002.
5. Wang, Y. & Narang, P. Anisotropic scattering in the goniopolar metal NaSn2As2. Phys. Rev. B
Condens. Matter 102, (2020).
6. Osterhoudt, G. B. et al. Evidence for Dominant Phonon-Electron Scattering in Weyl Semimetal
WP2. Physical Review X vol. 11 Preprint at https://doi.org/10.1103/physrevx.11.011017 (2021).
7. Coulter, J. et al. Uncovering electron-phonon scattering and phonon dynamics in type-I Weyl
semimetals. Phys. Rev. B Condens. Matter 100, 220301 (2019).
8. Garcia, C. A. C., Nenno, D. M., Varnavides, G. & Narang, P. Anisotropic phonon-mediated
electronic transport in chiral Weyl semimetals. Phys. Rev. Materials 5, L091202 (2021).
9. van Delft, M. R. et al. Sondheimer oscillations as a probe of non-ohmic flow in WP2 crystals. Nat.
Commun. 12, 4799 (2021).
10. Coulter, J., Sundararaman, R. & Narang, P. Microscopic origins of hydrodynamic transport in the
type-II Weyl semimetal WP2. Phys. Rev. B Condens. Matter 98, (2018).
11. Varnavides, G., Jermyn, A. S., Anikeeva, P. & Narang, P. Nonequilibrium phonon transport across
nanoscale interfaces. Phys. Rev. B Condens. Matter 100, 115402 (2019).
12. Zhao, B., Guo, C., Garcia, C. A. C., Narang, P. & Fan, S. Axion-Field-Enabled Nonreciprocal
Thermal Radiation in Weyl Semimetals. Nano Lett. 20, 1923–1927 (2020).
13. Nenno, D. M., Garcia, C. A. C., Gooth, J., Felser, C. & Narang, P. Axion physics in
condensed-matter systems. Nature Reviews Physics 2, 682–696 (2020).
14. Mu, Q.-G. et al. Suppression of axionic charge density wave and onset of superconductivity in the
chiral Weyl semimetal Ta2Se8I. Phys. Rev. Mater. 5, (2021).
Brief Bio: Dr. Prineha Narang is a Professor in Physical Sciences at UCLA. Prior to moving to UCLA,
she was an Assistant Professor of Computational Materials Science at Harvard University. Before
starting on the Harvard faculty in 2017, Dr. Narang was an Environmental Fellow at HUCE, and
worked as a research scholar in condensed matter theory in the Department of Physics at MIT. She
received an M.S. and Ph.D. in Applied Physics from Caltech. Her group works on theoretical and
computational quantum materials, non-equilibrium dynamics, and transport in quantum matter. In
2023 she was appointed a U.S. Science Envoy by the State Department to advance foreign policy
through scientific diplomacy and international cooperation. Narang’s work has been recognized by
many awards and special designations, including the 2023 Maria Goeppert Mayer Award from the
American Physical Society, 2022 Outstanding Early Career Investigator Award from the Materials
Research Society, Mildred Dresselhaus Prize, Bessel Research Award from the Alexander von
Humboldt Foundation, a Max Planck Award from the Max Planck Society, and the IUPAP Young
Scientist Prize in Computational Physics all in 2021, an NSF CAREER Award in 2020, being named
a Moore Inventor Fellow by the Gordon and Betty Moore Foundation, CIFAR Azrieli Global Scholar
by the Canadian Institute for Advanced Research, and a Top Innovator by MIT Tech Review (MIT
TR35). Narang has organized several symposia and workshops, most recently at the APS March
Meeting on “Materials for Quantum Information Science”. Her continued service to the community
includes chairing the Materials Research Society (MRS) Spring Meeting (2022) and the MRS-Kavli
Foundation Future of Materials Workshop: Computational Materials Science (2021), as an Associate
Editor at ACS Nano of the American Chemical Society, an Associate Editor at Applied Physics
Letters of the American Institute of Physics, organizing APS, Optica (OSA), and SPIE symposia, and
a leadership role in APS’ Division of Materials Physics. Outside of science, she is an avid triathlete,
runner, and starting her mountaineering journey.