Eminuscent phase in frustrated magnets: a challenge to quantum spin liquids

TL;DR

This paper investigates the low-temperature 'eminuscent' phase in frustrated magnets, revealing how impurity effects and a hidden energy scale may hinder the realization of quantum spin liquids.

Contribution

It introduces the concept of an 'eminuscent' phase driven by impurity interactions, challenging the pursuit of quantum spin liquids in clean frustrated magnets.

Findings

Glass-transition temperature increases as impurity concentration decreases.

A finite transition temperature persists even in impurity-free systems.

The 'eminuscent' phase may mask or prevent quantum spin liquid states.

Abstract

A geometrically frustrated (GF) magnet consists of localised magnetic moments, spins, whose orientation cannot be arranged to simultaneously minimise their interaction energies. Such materials may host novel fascinating phases of matter, such as fluid-like states called quantum spin liquids. GF magnets have, like all solid-state systems, randomly located impurities whose magnetic moments may ``freeze'' at low temperatures, making the system enter a spin-glass state. We analyse the available data for spin-glass transitions in GF materials and find a surprising trend: the glass-transition temperature grows with decreasing impurity concentration and reaches a finite value in the impurity-free limit at a previously unidentified, ``hidden'', energy scale. We propose a scenario in which the interplay of interactions and entropy leads to a crossover in the permeability of the medium that assists glass freezing at low temperatures. This low-temperature, ``eminuscent'', phase may obscure or even destroy the widely-sought spin-liquid states in rather clean systems.