Chiral $p$-wave superconductivity in a twisted array of proximitized quantum wires

TL;DR

This paper proposes a method to create a chiral $p$-wave superconductor using proximitized quantum wires arranged in a twisted array, which hosts Majorana zero modes and exhibits topological phases.

Contribution

It introduces a simple construction of a chiral superconductor through twisted arrays of proximitized quantum wires, enabling experimental exploration of Majorana modes.

Findings

A weakly coupled array of quantum wires forms a gapless $p$-wave superconductor.

Twisted stacking of two arrays induces a fully gapped $p_x+ip_y$ superconductor.

Majorana zero modes are demonstrated to exist in vortex defects.

Abstract

A superconductor with $p_x+ip_y$ order has long fascinated the physics community because vortex defects in such a system host Majorana zero modes. Here we propose a simple construction of a chiral superconductor using proximitized quantum wires and twist angle engineering as basic ingredients. We show that a weakly coupled parallel array of such wires forms a gapless $p$-wave superconductor. Two such arrays, stacked on top of one another with a twist angle close to $90^\circ$, spontaneously break time reversal symmetry and form a robust, fully gapped $p_x+ip_y$ superconductor. We map out topological phases of the proposed system, demonstrate existence of Majorana zero modes in vortices, and discuss prospects for experimental realization.