Viscous electron transport

Par Marco Polini, Instituto Italiano di Tecnologia, Graphene Labs, Genova, Italy and School of Physics and Astronomy, University of Manchester, Manchester UK

Jeudi 26 septembre,  14h00, Salle des séminaires (215), 2e étage, Bât. A4N

Abstract :

Frequent collisions between constituents in a classical or quantum liquid (like 3He) manifest through a transport coefficient called the shear viscosity [1]. The flow of these liquids, and also that of exotic quantum many-particle systems like ultracold 6Li atoms near a Feshbach resonance [2] and quark-gluon plasmas at relativistic heavy-ion colliders [3], is often described by three equations expressing the conservation of mass, momentum (the Navier-Stokes equation), and energy.
Realizing hydrodynamic transport in a solid has proven challenging, because of ever present processes that lead to momentum dissipation in the electron subsystem [4]. Even when suitable conditions are met, key questions have remained largely unexplored: how do you diagnose the emergence of hydrodynamic electron flow in a conventional field-effect transistor? How do you measure the viscosity of an electron liquid in such a setup? What is the impact of viscosity on electron transport?
In this talk I will try and answer these questions. I will first report on results of combined theoretical and experimental work [5,6,7] showing unambiguous evidence for the long-sought hydrodynamic solid-state transport regime. In particular, I will discuss how high-quality doped graphene sheets above liquid nitrogen temperatures exhibit negative non-local resistance near current injection points and whirlpools in the spatial current pattern [5,6,7]. Measurements of these non-local electrical signals allow to extract the value of the kinematic viscosity of the two-dimensional electron liquid in graphene, which is found to be an order of magnitude larger than that of honey and to compare well with many-body theoretical predictions [8]. I will then discuss viscous electron transport across a point contact [9] and ideas on how to probe hydrodynamic behavior via the use of engineered short-wavelength plasmon-phonon polaritons in hybrid stacks containing graphene, Boron Nitride, and metal gates [10,11].

References
[1] J.C.Maxwell, Philos. Trans. R. Soc. London 156, 249 (1866).
[2] C. Cao, E. Elliott, J. Joseph, H. Wu, J. Petricka, T. Schäfer, and J.E. Thomas, Science 331, 58 (2011).
[3] B.V. Jacak and B. Müller, Science 337, 310 (2012).
[4] R.N. Gurzhi, Sov. Phys. Uspekhi 11, 255 (1968).
[5] I. Torre, A. Tomadin, A.K. Geim, and M. Polini, Phys. Rev. B 92, 165433 (2015).
[6] D. Bandurin, I. Torre, R.K. Kumar, M. Ben Shalom, A. Tomadin, A. Principi, G.H. Auton, E. Khestanova, K.S. NovoseIov, I.V. Grigorieva, L.A. Ponomarenko, A.K. Geim, and M. Polini, Science 351, 1055 (2016).
[7] F.M.D. Pellegrino, I. Torre, A.K. Geim, and M. Polini, Phys. Rev. B 94, 155414 (2016).
[8] A. Principi, G. Vignale, M. Carrega, and M. Polini, Phys. Rev. B 93, 125410 (2016).
[9] R.K. Kumar, D.A. Bandurin, F.M.D. Pellegrino, Y. Cao, A. Principi, H. Guo, G.H. Auton, M. Ben Shalom, L.A. Ponomarenko, G. Falkovich, I.V. Grigorieva, L.S. Levitov, M. Polini, and A.K. Geim, Nature Phys. 13, 1182 (2017).
[10] M.B. Lundeberg, Y. Gao, R. Asgari, C. Tan, B. Van Duppen, M. Autore, P. Alonso-Gonzalez, A. Woessner, K. Watanabe, T. Taniguchi, R. Hillenbrand, J. Hone, M. Polini, and F.H.L. Koppens, Science 357, 187 (2017).
[11] I. Torre, L.V. de Castro, B. Van Duppen, D.B. Ruiz, F.M. Peeters, F.H.L. Koppens, and M. Polini, Phys. Rev. B 99, 144307 (2019).

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