Jeudi 26 novembre 2015 à 10h15
Salle 234, Ecole de Physique

Coherent caloritronics with topological edge states

Luca Vannucci, Università degli Studi di Genova, Italy

Coherent caloritronics is a new branch of physics that aims to coherently manipulate and control heat fluxes in solid state devices. In this context a great effort has been devoted to the realization of heat interferometers, heat transistors and thermal diodes. Moreover, the interplay between thermal and electrical transport is currently under investigation with the goal of realizing efficient thermoelectric devices. In this talk we show that the dissipationless topological edge states provide an excellent framework for coherent caloritronic devices and thermoelectric converters. We analyze the charge and heat current due to solely thermal gradients when the chiral edge states proper of the fractional Quantum Hall effect are tunnel coupled through a generic tunneling junction. We find that a setup made of multiple point-like contact effectively breaks the electron-hole symmetry, allowing for a thermoelectric charge current flowing either from hot to cold or vice versa, depending on the details of the tunnel junction. Correspondingly, an interference-induced heat current is predicted. Such a device can also serve as a thermal diode if consider two quantum Hall systems with different filling factors, and this effect can be enhanced by exploiting the interference properties of the tunnel junction. Finally we will discuss similar effects in the context of helical edge states of topological insulators. Here the spin degrees of freedom and the peculiar properties of these system, like the so-called spin-momentum locking, will allow for the coherent generation and manipulation of spin currents via thermoelectric effects.