Unconventional nonreciprocal voltage transition in Ag2Te nanobelts

Abstract

Abstract The nonreciprocal effect always emerges in noncentrosymmetric materials for the intrinsic symmetry broken and high conductivity systems for the extrinsic thermoelectric effect. Meanwhile, nonreciprocal charge transport is widely unitized as an effective experimental tool to detect electrical unidirectional intrinsic contribution. Here we show an unconventional nonreciprocal voltage transition in topological insulator Ag 2 Te nanobelts. The nonreciprocal voltage develops from nearly zero to giant values under the applied current I ac and external magnetic fields, while remaining unchanged under various current I dc . This electrical unidirectional contribution is further evidenced by the differential resistance (d V /d I ) measurements. Furthermore, the transition possesses two-dimensional properties under a tilted magnetic field and occurs when the voltage between two electrodes exceeds a certain value. We propose a possible mechanism based on the development of edge channels in Ag 2 Te nanobelts to interpret the phenomenon. Our results not only introduce a peculiar nonreciprocal voltage transition in topological materials but also enrich the understanding of the intrinsic mechanism that strongly affects the nonreciprocal charge transport.