Finite Field Transport Response of a Dilute Magnetic Topological Insulator-Based Josephson Junction

Abstract

Hybrid samples combining superconductors with magnetic topological insulators are a promising platform for exploring exotic new transport physics. We examine a Josephson junction of such a system based on the dilute magnetic topological insulator (Hg,Mn)Te and the type II superconductor MoRe. In the zero and very low field limits, to the best of our knowledge, the device shows, for the first time, an induced supercurrent through a magnetically doped semiconductor, in this case, a topological insulator. At higher fields, a rich and hysteretic magnetoresistance is revealed. Careful analysis shows that the explanation of this behavior can be found in magnetic flux focusing stemming from the Meissner effect in the superconductor, without invoking any role of proximity-induced superconductivity. The phenomena is important because it will ubiquitously coexist with any exotic new physics that may be present in this class of devices.

Field-free anomalous junction and superconducting diode effect in spin-split superconductor/topological insulator junctions

“…From the point of view of materials, the proposed structure can be fabricated with well-studied material combinations. On the one hand, the use of TIs in Josephson junctions is well understood [44,[48][49][50][51][52][53][54][55]. On the other hand, spin-split superconductivity has been measured in several experiments on FIS bilayers, as for example, EuS/Al structures [37,40,56,57].…”

Magnetically tunable supercurrent in dilute magnetic topological insulator-based Josephson junctions

“…This confirms a uniform current distribution across the width W of the JJ 26 . Flux focusing due to the Meissner effect from the long stripe-shaped superconducting leads (4 μm wide) determines the flux 27 .…”

“…The geometry and technology used to produce the JJs are the same as in ref. 27. Direct current I(V) measurements are performed using a quasi-four-probe configuration where the current is swept from negative to positive values for all the data presented here.…”