Bose metal near pair-density-wave order in a spin-orbit-coupled Kondo lattice

TL;DR

This paper predicts a Bose metal phase in a 3D superconductor with non-Abelian SU(2) order, characterized by strong fluctuations and a resistivity scaling as T^3, arising from a solvable Kondo lattice model.

Contribution

It introduces a novel Bose metal phase near a pair-density-wave order in a spin-orbit-coupled Kondo lattice with SU(2) symmetry, supported by analytical fluctuation analysis.

Findings

Resistivity scales as approximately T^3 in the disordered phase.

Soft modes form a ring of low-energy excitations throughout the phase.

Strong fluctuations prevent conventional superconducting order near the Lifshitz point.

Abstract

We show that a three-dimensional superconductor with a non-Abelian SU(2) order parameter can support an extended resistive regime a Bose metal, in which transport is carried by bosonic electron-Majorana bound states - separating a uniform superconductor from a pair-density-wave (PDW) phase. The setting is a solvable Kondo lattice model introduced previously by the present authors, in which Kondo screening of a Yao-Lee $\mathbb{Z}_2$ spin liquid generates an order parameter with SU(2), rather than conventional U(1), symmetry, containing both superconducting and spin-density-wave components. Two effects cooperate to make fluctuations anomalously strong in three dimensions: the vanishing of the quadratic superconducting stiffness near the Lifshitz point where the optimal pairing momentum shifts from zero to finite $Q$, and the enlarged SU(2) order-parameter manifold. Building on our prior result that doping away from half-filling drives amplitude-modulated PDW order via finite-momentum electron-Majorana condensation, we analyze the fluctuation-dominated regime above that phase using a nonlinear sigma model. We find that the order-parameter propagator develops a ring of soft modes throughout the disordered phase, and that the resulting resistivity scales approximately as $R \sim T^3$ in three dimensions.