Quantum Hall effects in layered disordered superconductors

TL;DR

This paper investigates quantum Hall effects in disordered layered superconductors, revealing phase diagrams with charge-spin separation, multiple spin Hall phases, and critical exponents, advancing understanding of topological phases in disordered superconducting systems.

Contribution

It introduces a detailed phase diagram for disordered layered superconductors showing novel quantum Hall and spin phases, including effects of Zeeman terms, with critical exponents.

Findings

Identification of quantum Hall phases with spin Hall coefficients 0, 1, and 2

Discovery of a spin metal phase separating quantum Hall states

Determination of a spin conductivity exponent of approximately 0.9

Abstract

Layered singlet paired superconductors with disorder and broken time reversal symmetry are studied. The phase diagram demonstrates charge-spin separation in transport. In terms of the average intergrain transmission and the interlayer tunnelling we find quantum Hall phases with spin Hall coefficients of 0 and 2 separated by a spin metal phase. We identify a spin metal-insulator localization exponent as well as a spin conductivity exponent of ~0.9. In presence of a Zeeman term an additional phase with spin Hall coefficient of 1 appears.