论文标题
加压FETE0.55SE0.45中费米表面重建与超导性之间的相关性
Correlation between Fermi surface reconstruction and superconductivity in pressurized FeTe0.55Se0.45
论文作者
论文摘要
在这里，我们报告了在推定的拓扑超导体FETE0.55SE0.45上，在不同温度下，高压霍尔系数（RH）测量以及高压电阻测量的第一个结果。我们发现RH的符号变化的紧密相关性，RH的指纹是通过结构相变和超导性来体现费米表面重建的指纹。在2.7 GPA的临界压力（PC）以下，我们的数据表明，孔 - 电子载体在临界温度（T*）下是热平衡（RH = 0），其中RH将其符号从正变为阴性，并且同时发生了四方正骨相位过渡。在从1BAR到PC的压力范围内，T*通过压力不断抑制，而TC则单调增加。在大约PC上，T*是无法区分的，TC达到最大值。此外，在〜PC上发现了压力诱导的符号变化，其中正骨 - 单斜相变发生。随着进一步的压缩，TC在〜12 GPA下降低并消失。在加压的FETE0.55SE0.45中发现的电子孔平衡，晶体结构和超导性之间的相关性意味着其非平凡的超导性与其外来正常状态密切相关，这是由于Fermi表面的重建与结构晶状体的变化之间的相互作用所致。
Here we report the first results of the high-pressure Hall coefficient (RH) measurements, combined with the high-pressure resistance measurements, at different temperatures on the putative topological superconductor FeTe0.55Se0.45. We find the intimate correlation of sign change of RH, a fingerprint to manifest the reconstruction of Fermi surface, with structural phase transition and superconductivity. Below the critical pressure (PC) of 2.7 GPa, our data reveal that the hole - electron carriers are thermally balanced (RH=0) at a critical temperature (T*), where RH changes its sign from positive to negative, and concurrently a tetragonal-orthorhombic phase transition takes place. Within the pressure range from 1bar to PC, T* is continuously suppressed by pressure, while TC increases monotonically. At about PC, T* is indistinguishable and TC reaches a maximum value. Moreover, a pressure-induced sign change of RH is found at ~PC where the orthorhombic-monoclinic phase transition occurs. With further compression, TC decreases and disappears at ~ 12 GPa. The correlation among the electron-hole balance, crystal structure and superconductivity found in the pressurized FeTe0.55Se0.45 implies that its nontrivial superconductivity is closely associated with its exotic normal state resulted from the interplay between the reconstruction of the Fermi surface and the change of the structural lattice.
