An Anomalously Elastic, Intermediate Phase in Randomly Layered Superfluids, Superconductors, and Planar Magnets

TL;DR

This paper uncovers an intermediate phase in layered disordered systems like magnets and superconductors where perpendicular stiffness shows anomalous scaling, while parallel stiffness and magnetization stay finite, revealing new universal behavior.

Contribution

It introduces the concept of an anomalously elastic intermediate phase caused by layered quenched randomness, with detailed analysis of phase transitions and universality.

Findings

Perpendicular spin-wave stiffness exhibits anomalous scaling with a variable exponent.

Parallel stiffness and magnetization remain finite in the intermediate phase.

Results are applicable to superfluids, superconductors, and planar magnets.

Abstract

We show that layered quenched randomness in planar magnets leads to an unusual intermediate phase between the conventional ferromagnetic low-temperature and paramagnetic high-temperature phases. In this intermediate phase, which is part of the Griffiths region, the spin-wave stiffness perpendicular to the random layers displays anomalous scaling behavior, with a continuously variable anomalous exponent, while the magnetization and the stiffness parallel to the layers both remain finite. Analogous results hold for superfluids and superconductors. We study the two phase transitions into the anomalous elastic phase, and we discuss the universality of these results, and implications of finite sample size as well as possible experiments.