Microscopic study of supercurrent diode effect in chiral nanotubes

TL;DR

This paper provides a microscopic, quantitative analysis of the supercurrent diode effect in chiral nanotubes, revealing how various parameters influence the effect and clarifying its microscopic origins.

Contribution

It offers the first microscopic, lattice-model-based study of the supercurrent diode effect in chiral nanotubes, including TMDs and carbon nanotubes, with detailed parameter dependence analysis.

Findings

Sign flipping of SDE occurs with parameter changes.

Comparison of TMD nanotubes with and without spin-orbit coupling.

Effects of strain on the supercurrent diode effect.

Abstract

Nonreciprocity of supercurrents may exist when both spatial inversion and time-reversal symmetries are broken, leading to the supercurrent diode effect (SDE). The spatial inversion symmetry may be broken by chiral structures in nanotubes where the SDE is expected when a magnetic flux passes through the tube. While such an effect has been predicted based on a phenomenological theory, a microscopic and quantitative study with a concrete lattice model is missing. Here, we investigate the SDE in chiral nanotubes made of carbon and those made of transition metal dichalcogenides (TMD) with tight-binding models. We obtain the SDE efficiency as a function of the nanotube radius, the chiral angle, the magnetic flux, the temperature, the chemical potential, etc., and find that sign flipping happens in various parameter dependencies. In TMD nanotubes, the SDEs with and without the spin-orbit coupling are compared. We also simulate CNTs made from square lattice materials for comparison and discuss the effects of strains. Besides qualitative consistency with previous phenomenological theory, new features are found and the microscopic origins are clarified.