Temperature - Pressure phase diagram of the cubic Laves phase Au$_2$Pb

TL;DR

This study maps the temperature-pressure phase diagram of Au$_2$Pb, revealing multiple structural transitions and superconducting phases, highlighting its potential for exploring the interplay of structure, topology, and electronic properties.

Contribution

It provides the first detailed T-P phase diagram of Au$_2$Pb, showing how pressure influences structural phases and superconductivity, and suggests its suitability for studying topological and structural interactions.

Findings

Multiple structural phase transitions at ambient pressure.

Pressure induces new phases with superconductivity.

Strong evolution of transition temperatures with pressure.

Abstract

The temperature ($T$) as a function of pressure ($P$) phase diagram is reported for the cubic Laves phase compound Au$_2$Pb, which was recently proposed to support linearly dispersing "topological" bands, together with conventional quadratic bands. At ambient pressure, Au$_2$Pb exhibits several structural phase transitions at $T_1$ $=$ 97 K, $T_2$ $=$ 51 K, and $T_3$ $=$ 40 K with superconductivity below $T_{\rm{c}}$ $=$ 1.2 K. Applied pressure results in a rich phase diagram where $T_1$, $T_2$, and $T_3$ evolve strongly with $P$ and a new phase is stabilized for $P$ $>$ 0.64 GPa that also supports superconductivity below 1.1 K. These observations suggest that Au$_2$Pb is an ideal system in which to investigate the relationship between structural degrees of freedom, band topology, and resulting anomalous behaviors.