Temperature-pressure phase diagram of cubic Laves phaseAu2Pb

The temperature $(T)$ as a function of pressure $(P)$ phase diagram is reported for the cubic Laves phase compound ${\mathrm{Au}}₂\text{Pb}$, which was recently proposed to support linearly dispersing topological bands, together with conventional quadratic bands. At ambient pressure, ${\mathrm{Au}}₂\text{Pb}$ exhibits several structural phase transitions at ${T}₁=97\text{K}$, ${T}₂=51\text{K}$, and ${T}₃=40\text{K}$ with superconductivity below ${T}_{\mathrm{c}}=1.2\text{K}$. Applied pressure results in a rich phase diagram where ${T}₁,{T}₂$, and ${T}₃$ evolve strongly with $P$ and a possible new phase is stabilized for $P>0.64$ GPa that also supports superconductivity below 1.1 K. These observations suggest that ${\mathrm{Au}}₂\text{Pb}$ is an ideal system in which to investigate the relationship between structural degrees of freedom, band topology, and resulting anomalous behaviors.