Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 57: Organic Photovoltaics and Electronics II (joined session with CPP)
HL 57.7: Vortrag
Mittwoch, 22. März 2017, 16:45–17:00, POT 81
Intereference-induced thermoelectric effects in topological states of matter — •Flavio Ronetti1,2, Luca Vannucci1,2, Giacomo Dolcetto3, Matteo Carrega4, and Maura Sassetti1,2 — 1Dipartimento di Fisica, Università di Genova,Via Dodecaneso 33, 16146, Genova, Italy. — 2CNR-SPIN, Via Dodecaneso 33, 16146, Genova, Italy. — 3Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg. — 4NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.
In topological states of matter, such as edge states of quantum Hall systems and two-dimensional topological insulators, protection from backscattering guarantees phase-coherent ballistic transport, allowing for the observation of quantum interference effects. Intriguing thermoelectric properties can be achieved by exploiting the phase-coherent edge states of two quantum Hall systems coupled by tunnelling region. Considering a multiple quantum point contacts geometry, interference paths effectively break the electron-hole symmetry. Therefore, when the systems are driven out of equilibrium by a thermal gradient, a thermoelectric charge current can be induced. Correspondingly, an interference pattern in the heat current is predicted. In the case of two-dimensional topological insulators, the presence of spin degree of freedom give rise to a rich tunnelling dynamics. In a double quantum point contact geometry, the effective transmission related to spin-flipping processes acquires a functional dependence on energy in the interacting regime, thus generating a thermoelectric spin current in response to a thermal gradient.