Phase-Tunable Thermal Rectification in the Topological SQUIPT

We theoretically explore the behavior of thermal transport in the topological SQUIPT, in the linear and nonlinear regime. The device consists of a topological Josephson junction based on a two-dimensional topological insulator in contact with two superconducting leads, and a probe tunnel coupled to the topological edge states of the junction. We compare the performance of a normal metal and a graphene probe, showing that the topological SQUIPT behaves as a passive thermal rectifier and that it can reach a rectification coefficient of up to 145% with the normal metal probe. Moreover, the interplay between the superconducting leads and the helical edge states leads to a unique behavior due to a Doppler-shift-like effect that allows one to influence quasiparticle transport through the edge channels via the magnetic flux that penetrates the junction. Exploiting this effect, we can greatly enhance the rectification coefficient for temperatures below the critical temperature TC in an active rectification scheme.