Reference : Topological Andreev Rectification
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Physics and Materials Science
Topological Andreev Rectification
Tam, Pok Man [University of Pennsylvania - Penn > Physics and Astronomy]
De Beule, Christophe mailto [University of Luxembourg > Faculty of Science, Technology and Medicine (FSTM) > Department of Physics and Materials Science (DPHYMS) >]
Kane, Charles L [University of Pennsylvania - Penn > Physics and Astronomy]
Physical Review. B
American Physical Society
College Park
United States - Maryland
[en] We develop the theory of an Andreev junction, which provides a method to probe the intrinsic topology of the Fermi sea of a two-dimensional electron gas (2DEG). An Andreev junction is a Josephson π junction proximitizing a ballistic 2DEG, and exhibits low-energy Andreev bound states that propagate along the junction. It has been shown that measuring the nonlocal Landauer conductance due to these Andreev modes in a narrow linear junction leads to a topological Andreev rectification (TAR) effect characterized by a quantized conductance that is sensitive to the Euler characteristic χF of the 2DEG Fermi sea. Here we expand on that analysis and consider more realistic device geometries that go beyond the narrow linear junction and fully adiabatic limits considered earlier. Wider junctions exhibit additional Andreev modes that contribute to the transport and degrade the quantization of the conductance. Nonetheless, we show that an appropriately defined rectified conductance remains robustly quantized provided large momentum scattering is suppressed. We verify and demonstrate these predictions by performing extensive numerical simulations of realistic device geometries. We introduce a simple model system that demonstrates the robustness of the rectified conductance for wide linear junctions as well as point contacts, even when the nonlocal conductance is not quantized. Motivated by recent experimental advances, we model devices in specific materials, including InAs quantum wells, as well as monolayer and bilayer graphene. These studies indicate that for sufficiently ballistic samples observation of the TAR effect should be within experimental reach.
Fonds National de la Recherche - FnR
FnR ; FNR16515716 > Christophe De Beule > ESRMOIRE > Electronic States And Responses In Moiré Heterostructures > 01/02/2022 > 31/01/2023 > 2021

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