Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 36: Superconductivity: Theory I
TT 36.5: Vortrag
Mittwoch, 20. März 2024, 10:30–10:45, H 3005
Thermoelectric Switch From Bogoliubov Fermi Surface in superconducting 3D Topological Insulator Heterostructures — •Phillip Mercebach1, Bo Lu2, Keiji Yada3, Yukio Tanaka3, and Pablo Burset1 — 1Department of Theoretical Condensed Matter Physics, Condensed Matter Physics Center (IFIMAC) and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, 28049 Madrid, Spain — 2Department of Physics, Tianjin University, Tianjin 300072, China — 3Department of Applied Physics, Nagoya University, Nagoya 464-8603, Japan
A weak magnetic field applied to a superconductor (SC) can selectively close the superconducting gap, giving rise to a segmented Fermi surface. So-called Bogoliubov Fermi surfaces (BFSs) have been observed in recent experiments in a three-dimensional topological insulator (3DTI) in proximity to a SC. Here, we employ a scattering matrix formalism to reveal signatures of the BFS in the thermoelectric transport properties of a superconducting hybrid junction on the surface of a 3DTI. We consider a setup with two normal probes (N) connected to a SC (N-SC-N configuration) to study local and nonlocal transport under an applied in-plane magnetic field. With a temperature gradient, the magnetic field creates equal local and nonlocal electric Seebeck currents which follow the orientation of the BFS. Furthermore, we predict a switch in the required voltage bias enabling local and nonlocal Peltier cooling, which again depends on the orientation of the BFS. As a result, our work opens new perspectives for applications in spintronics and exploring unconventional superconducting phases.
Keywords: Bogoliubov Fermi Surface; 3-dimensional topological insulator; Thermoelectricity; Dirac material; Mesoscopic transport