Pressure-induced enhancement of superconductivity and suppression of semiconducting behavior in LnO0.5F0.5BiS2 (Ln=La,Ce) compounds

Abstract

Electrical resistivity measurements as a function of temperature between 1 and 300 K were performed at various pressures up to 3 GPa on the superconducting layered compounds LnO0.5F0.5BiS2 (Ln = La, Ce). At atmospheric pressure, LaO0.5F0.5BiS2 and CeO0.5F0.5BiS2 have superconducting critical temperatures Tc of 3.3 and 2.3 K, respectively. For both compounds, the superconducting critical temperature Tc initially increases, reaches a maximum value of 10.1 K for LaO0.5F0.5BiS2 and 6.7 K for CeO0.5F0.5BiS2, and then gradually decreases with increasing pressure. Both samples also exhibit transient behavior in the region between the lower Tc phase near atmospheric pressure and the higher Tc phase at higher pressures. This region is characterized by a broadening of the superconducting transition, in which Tc and the transition width ΔTc are reversible with increasing and decreasing pressure. There is also an appreciable pressure-induced and hysteretic suppression of semiconducting behavior up to the pressure at which the maximum value of Tc is found. At pressures above the value at which the maximum in Tc occurs, there is a gradual decrease of Tc and further suppression of the semiconducting behavior with pressure, both of which are reversible.

Source-reported materials — not catalogue approval

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