Magnetic Monopole Supercurrent through a Quantum Spin Ice Tunnel Junction

TL;DR

This paper predicts a novel supercurrent of magnetic monopoles in a quantum spin ice system, enabled by phase differences induced by electric voltages, opening new avenues for dissipationless spin control.

Contribution

It introduces the concept of monopole supercurrent through a quantum spin ice junction driven by gauge-invariant phase differences, a novel phenomenon in spintronics.

Findings

Monopole supercurrent flows across a quantum spin ice junction.

Phase difference induced by electric voltage enables supercurrent.

Potential for dissipationless control of magnetism in spintronics.

Abstract

Magnetic monopoles are hypothetical particles that may exist as quantized sources and sinks of the magnetic field. In materials, they may appear in an emergent quantum electrodynamics described by a U(1) lattice gauge theory. Particularly, quantum spin ice hosts monopoles as bosonic spinons coupled to emergent gauge fields in a U(1) quantum spin liquid, namely, a deconfined Coulomb phase. When monopoles are condensed to form a long-range order, monopoles and gauge fields are screened and confined. Here we show, however, that monopole supercurrent flows across a junction of two ferromagnets that are weakly linked through and placed on top of the U(1) QSL, when a gauge-invariant phase difference of spinons across the junction is generated by quenching or an applied electric voltage parallel to the junction. This novel phenomenon paves the way to a new paradigm of spinonics for a dissipationless control of magnetism.