Quantum Critical Scaling of Specific Heat in a Quasicrystal

TL;DR

This study investigates the quantum critical behavior of specific heat in a quasicrystal, revealing power-law divergences and a scaling function that describes the transition from temperature- to field-limited quantum critical regimes.

Contribution

It introduces a scaling function for the specific heat in a quasicrystal near quantum criticality, highlighting the role of magnetic field as a cutoff for critical fluctuations.

Findings

Zero-field specific heat diverges as T^{-0.54}

High-field specific heat scales as B^{-0.50}

Two anomalies observed at 0.7 K and 2.1 K

Abstract

In strongly correlated systems, interactions give rise to critical fluctuations surrounding the quantum critical point (QCP) of a quantum phase transition. Quasicrystals allow the study of quantum critical phenomena in aperiodic systems with frustrated magnetic interactions. Here, we study the magnetic field and temperature scaling of the low-temperature specific heat for the quantum critical Yb-Au-Al quasicrystal. We devise a scaling function that encapsulates the limiting behaviors as well as the area where the system goes from a temperature-limited to a field-limited quantum critical region, where magnetic field acts as a cutoff for critical fluctuations. The zero-field electronic specific heat is described by a power-law divergence, ${C_{el}/T \propto T^{-0.54}}$, aligning with previously observed ac-susceptibility and specific heat measurements. The field dependence of the electronic specific heat at high magnetic fields shows a similar power-law ${C_{el}/T \propto B^{-0.50}}$. In the zero-field and low-field region, we observe two small but distinct anomalies in the specific heat, located at 0.7 K and 2.1 K.