Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 20: Quantum Dots and Quantum Wires (joint session TT/HL)
TT 20.3: Vortrag
Montag, 18. März 2024, 17:15–17:30, H 3007
Spatially-resolved dissipation in a quantum wire with a coherent scatterer — •Nico Leumer1,2, Denis Basko3, Rodolfo Jalabert1, Dietmar Weinmann1, and Robert Whitney3 — 1IPCMS, France — 2DIPC, Spain — 3LPMMC, France
The recent advent of astonishing measurement techniques allows the near-atomic resolution of tiny local temperature changes, even three orders of magnitude lower than the sample temperature itself [1]. The new approaches confirmed earlier estimations that dissipation (accompanying electric current) is not shared equally among two 1d wires attached to a point contact. Moreover, the formation of so called heat-spots (small and confined areas of increased temperature) were observed in the quantum regime [2]. Evidently, dc charge transport possesses the key to further unravel the microscopic mechanisms behind spatial dissipation profiles.
Based on a model of two 1d wires sandwiching a scatterer, we investigated the spatial distribution of the dissipated power for generic transmission of the scatterer. We present the mechanism behind the formation of heat/ cold spots and the key role of the electric potential, which is required to maintain the electric current against the increased wire’s resistivity in close vicinity to the point contact. Additionally, we report on the self-consistent calculation of the steady state current which obeys a four-point Landauer type relation w.r.t. the voltage drop inside the scatterer.
[1] D. Halbertal et al., Nature 539 (2016) 407
[2] Q. Weng et al., Nat. Commun. 12 (2021) 4752
Keywords: Spatially resolved dissipation; Heat/cold spots