Pressure-dependent modifications in the LaAuSb2 charge density wave system

Abstract

Hydrostatic pressure response of $\mathrm{LaAu}{\mathrm{Sb}}_{2}$ charge density wave (CDW) system is investigated using electrical transport, x-ray diffraction (XRD), and density-functional theory (DFT). Resistivity data at ambient pressure evidence a clear CDW transition at 83 K. X-ray diffraction at ambient pressure reveals that in plane and out of plane axes show opposite behavior with decreasing temperature, in particular, out of plane $c$ axis develops a distinct change at \ensuremath{\sim}250 K, much above the observed CDW transition at 83 K. The CDW transition shifts to low temperature with increasing pressure. Our resistivity data indicate a complete suppression of the CDW transition at \ensuremath{\sim}3.6 GPa. High-pressure XRD revealed a change from the linear trend for the out of plane ($c$) and the in plane ($a$) lattice parameters for pressure above 3.8 GPa. With compression, DFT indicated an anomaly in the c/a ratio around 8 GPa. The calculated electronic structure also indicated minor changes in the band structure in this pressure range. In addition, high-pressure DFT structural investigations reveal the $\mathrm{LaAu}{\mathrm{Sb}}_{2}$ system to be stable up to pressures as high as 150 GPa.