Multiple superconducting phases driven by pressure in the topological insulator GeSb 4 Te 7

作者：Wei Zhou, Bin Li, Yi Shen, Jiaqi Feng, Chunqiang Xu, Hui Guo, Zhihao He, Bin Qian, Ziming Zhu, Xiaofeng Xu · 发表于：Physical review. B./Physical review. B · 年份：2023 · DOI：10.1103/physrevb.108.184504 · 被引用次数：6 · 研究领域：Topological Materials and Phenomena、Graphene research and applications、Advanced Condensed Matter Physics

Tuning superconductivity in topological materials by means of chemical substitution, electrostatic gating, or pressure is thought to be an effective route towards realizing topological superconductivity with their inherent Majorana fermions, the manipulation of which may form the basis for future topological quantum computing. It has recently been established that the pseudo-binary chalcogenides (${ACh)}_{m}{(P{n}_{2}C{h}_{3})}_{n}$ ($A=\text{Ge}$, Mn, Pb, etc.; $Pn=\text{Sb}$ or Bi; $Ch=\text{Te}$, Se) may host novel topological quantum states such as the quantum anomalous Hall effect and topological axion states. Here we map out the phase diagram of one member in this series, the topological insulator candidate ${\mathrm{GeSb}}_{4}{\mathrm{Te}}_{7}$ up to pressures of $\ensuremath{\sim}35$ GPa, through a combination of electrical resistance measurements, Raman spectroscopy, as well as first-principles calculations. Three distinct superconducting phases emerge under the pressure above $\ensuremath{\sim}11, \ensuremath{\sim}17$, and $\ensuremath{\sim}31$ GPa, which are accompanied by concomitant structural transitions, evidenced from the changes in the Raman modes. The first-principles calculations validate the existence of a topological insulating state at ambient pressure and predict two possible structural transitions at 10 and 17 GPa, in agreement with the experimental observations. Overall, our results establish the ${\mathrm{GeSb}}_{4}{\mathrm{Te}}_{7}$ family of materi...