Highly responsive ground state of PbTaSe${}_2$: structural phase transition and evolution of superconductivity under pressure

Abstract

Transport and magnetic studies of PbTaSe${}_2$ under pressure suggest existence of two superconducting phases with the low temperature phase boundary at $\sim 0.25$ GPa that is defined by a very sharp, first order, phase transition. The first order phase transition line can be followed via pressure dependent resistivity measurements, and is found to be near 0.12 GPa near room temperature. Transmission electron microscopy and x-ray diffraction at elevated temperatures confirm that this first order phase transition is structural and occurs at ambient pressure near $\sim 425$ K. The new, high temperature / high pressure phase has a similar crystal structure and slightly lower unit cell volume relative to the ambient pressure, room temperature structure. Based on first-principles calculations this structure is suggested to be obtained by shifting the Pb atoms from the $1a$ to $1e$ Wyckoff position without changing the positions of Ta and Se atoms. PbTaSe${}_2$ has an exceptionally pressure sensitive, structural phase transition with $\Delta T_s/\Delta P\approx -1700$ K/GPa near 4 K, this first order transition causes an $\sim 1$ K ($\sim 25\%$) step - like decrease in $T_c$ as pressure is increased through 0.25 GPa.

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Cited by in corpus (8)

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• Topological Phase Transition Under Pressure in the Topological Nodal Line Superconductor PbTaSe${}_2$
• Collapsed Tetragonal Phase Transition in LaRu${}_2$P${}_2$
• Electronic structure of topological superconductor candidate Au${}_2$Pb
• Commensurate stacking phase transitions in an intercalated transition metal dichalcogenide
• Effect of pressure on the physical properties of the superconductor NiBi3
• Pressure-induced multiple phase transformations of the BaBi${}_3$ superconductor
• Anomalous Nernst Effect in Nonmagnetic Nodal Line Semimetal PbTaSe${}_2$