Pressure-induced multiple phase transformations of the BaBi3 superconductor

Abstract

Measurements of temperature-dependent resistance and magnetization under hydrostatic pressures up to 2.13 GPa are reported for single-crystalline, superconducting BaBi3. A temperaturepressure phase diagram is determined and the results suggest three different superconducting phases α, β, and γ in the studied pressure range. We further show that occurrence of the three superconducting phases is intuitively linked to phase transitions at higher temperature which are likely first order in nature. Tp, which separates phase α from β and γ, is associated with an abrupt resistance change as pressure is increased from 0.27 GPa to 0.33 GPa. Above 0.33 GPa, an "S-shape" anomaly in the temperature-dependent resistance curve, TS, is observed and associated with the transition between the β and γ phases. Further increasing of pressure above 1.05 GPa suppresses this transition and BaBi3 stays in γ phase over the whole investigated temperature range. These high-temperature anomalies are likely related to structural degrees of freedom. With the α phase being the ambient-pressure tetragonal structure (P 4/mmm), our first-principle calculations suggest the β phase to be cubic structure (P m − 3m) and the γ phase to be a distorted tetragonal structure where the Bi atoms are moved out of the face-centered position. Finally, an analysis of the evolution of the superconducting upper critical field with pressure further confirms these transitions in the superconducting state and suggests a possible change of band structure or a Lifshitz transition near 1.54 GPa in γ phase. Given the large atomic numbers of both Ba and Bi, our results establish BaBi3 as a good candidate for the study of the interplay of structure with superconductivity in the presence of strong spin-orbit coupling.

Superconductivity in topological insulator β-PdBi2 under pressure

“…One of the possible factor may be phonon softening. In fact, the constant T c -p behavior may be characteristic because various Bi compounds (Bi [41] and BaBi 3 [42]) demonstrated a constant T c against pressure. Moreover, the T c -p behavior for α-PdBi 2 provided an almost constant T c with increasing pressure [29].…”

Physical properties of RBi2 (R=La,Ce) under pressure

“…Bi-rich compounds manifest a rich variety of ground states. For example, Bi-based families such as ABi (A = Li and Na) 1,2 , ABi 2 (A = K, Rb, Cs and Ca) 3,4 and ABi 3 (A = Sr, Ba, Ca, Ni, Co, and La) are superconducting (SC) at low temperature [5][6][7][8][9][10] . RBi (R = Ce, Nd, Tb and Dy) and RBi 2 (R = La-Nd, Sm) families have lowtemperature magnetic ground states with complex H −T phase diagrams 11,12 .…”

Pressure tuning of correlated electron systems

“…Note that BaBi 3 is air sensitive, thus XRD measurements and electrical contacts were performed in the glovebox with ambient pressure N 2 gas condition. This work is published in Ref Xiang et al (2018b)…”