Abstract
We measure electron transport through point contacts in an electron gas in AlGaAs/GaAs heterostructures and graphene for a range of temperatures, magnetic fields, and electron densities. We find a magnetoconductance peak around B=0. With increasing temperature, the width of the peak increases monotonically, while its amplitude first increases and then decreases. For GaAs point contacts the peak is particularly sharp at relatively low temperatures T≈1.5K: the curve rounds on a scale of a few tens of microteslas, hinting at length scales of several millimeters for the corresponding scattering processes. We propose a model based on the transition between different transport regimes with increasing temperature: from ballistic transport to few electron-electron scatterings to hydrodynamic superballistic flow to hydrodynamic Poiseuille-like flow. The model is in qualitative and, in many cases, quantitative agreement with the experimental observations. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000640784Publication status
publishedExternal links
Journal / series
Physical Review ResearchVolume
Pages / Article No.
Publisher
American Physical SocietyOrganisational unit
03439 - Ensslin, Klaus / Ensslin, Klaus
08835 - Ihn, Thomas (Tit.-Prof.)
02205 - FIRST-Lab / FIRST Center for Micro- and Nanoscience
03833 - Wegscheider, Werner / Wegscheider, Werner
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