Interplay between charge density wave order and superconductivity in La Au Sb 2 under pressure

We report superconductivity below ${T}_{\mathrm{c}}=0.64$ K in the charge density wave (CDW) ordered material ${\mathrm{LaAuSb}}_{2}$, from measurements of the electrical resistivity, specific heat, and ac magnetic susceptibility. To investigate the interplay between superconductivity and CDW order in ${\mathrm{LaAuSb}}_{2}$, we measured the resistivity under pressures up to 2.0 GPa and constructed the temperature-pressure phase diagram. With the application of pressure, ${T}_{\mathrm{c}}$ increases gradually before exhibiting a sudden jump at around 0.64 GPa, while the CDW order is suppressed to lower temperatures before abruptly vanishing at the same pressure. We suggest that the jump of ${T}_{\mathrm{c}}$ may be due to the enhancement of the density of states with the closure of the CDW energy gap when CDW order is suppressed. On the other hand, the normalized upper critical field ${H}_{\mathrm{c}2}$ changes little with pressure, suggesting that orbital limiting is the dominant pair-breaking mechanism in ${\mathrm{LaAuSb}}_{2}$.