Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 51: Transport Properties (joint session HL/TT)

HL 51.7: Talk

Thursday, March 20, 2025, 16:45–17:00, H13

Anomalous Knudsen effect signaling long-lived modes in 2D electron gases — •Grigorii Starkov and Björn Trauzettel — Institute for Theoretical Physics and Astrophysics, University of Würzburg, D-97074 Würzburg, Germany

Careful analysis of electron collisions in two spatial dimensions leads to the conclusion, that the odd harmonics of the electron distribution function decay much slower in comparison to the even ones at finite temperatures. Focusing on a channel geometry with boundary scattering, we show, that such behaviour of the odd decay rates leads to a characteristic behaviour of the resistance that we dub anomalous Knudsen effect: increasing temperature leads to decreasing resistance, that quickly slows down and turns into growth. The further increase of temperature exhibits the usual Gurzhi peak in the resistance related to the crossover from ballistic to hydrodynamic transport. The simultaneous observation of the Gurzhi peak preceded by an anomalous Knudsen dip can serve as a concrete signature of the long-lived modes in the 2D electron transport at low temperatures.

Keywords: Transport properties; 2D Materials; Boltzmann Equation; long-lived excitatioins