Emergence of mesoscale quantum phase transitions in a ferromagnet

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

Mesoscale patterns as observed in, for example, ferromagnets, ferroelectrics, superconductors, monomolecular films or block copolymers1,2 reflect spatial variations of a pertinent order parameter at length scales and time scales that may be described classically. This raises the question for the relevance of mesoscale patterns near zero-temperature phase transitions, also known as quantum phase transitions. Here we report the magnetic susceptibility of LiHoF4—a dipolar Ising ferromagnet—near a well-understood transverse-field quantum critical point (TF-QCP)3,4. When tilting the magnetic field away from the hard axis such that the Ising symmetry is always broken, a line of well-defined phase transitions emerges from the TF-QCP, characteristic of further symmetry breaking, in stark contrast to a crossover expected microscopically. We show that the scenario of a continuous suppression of ferromagnetic domains, representing a breaking of translation symmetry on mesoscopic scales in an environment of broken magnetic Ising symmetry on microscopic scales, is in excellent qualitative and quantitative agreement with the field and temperature dependence of the susceptibility and the magnetic phase diagram of LiHoF4 under tilted field. This identifies a new type of phase transition that may be referred to as mesoscale quantum criticality, which emanates from the textbook example of a microscopic ferromagnetic TF-QCP. Our results establish the surroundings of quantum phase transitions as a regime of mesoscale pattern formation, in which non-analytical quantum dynamics and materials properties without classical analogue may be expected.

Details

Original languageEnglish
Pages (from-to)65-70
Number of pages6
JournalNature
Volume609
Publication statusPublished - 31 Aug 2022
Peer-reviewedYes

External IDs

Mendeley 301815ec-a1f2-37df-b78a-49b847d8772d
WOS 000849436200010
Scopus 85137039145

Keywords

ASJC Scopus subject areas

Keywords

  • Non-fermi-liquid, Lithium holmium fluoride, Critical-behavior, Domain-structure, Dynamics, Lihof4, State, Magnetization, Size