Electronic multipoles and multiplet pairs induced by Pomeranchuk and Cooper instabilities of Bogoliubov Fermi surfaces
Electronic multipoles and multiplet pairs induced by Pomeranchuk and Cooper instabilities of Bogoliubov Fermi surfaces
复制标题
Bogoliubov 费米面的 Pomeranchuk 和 Cooper 不稳定性引起的电子多极子和多重态对
DOI：
10.1103/physrevb.102.024505
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
S. Hoshino
中科院分区：
文献类型：
--
作者：
S.-T. Tamura;S. Iimura;S. Hoshino
最近有人指出，在对称的自旋-轨道相互作用和时间反演对称性破缺的情况下，费米面仍然存在。利用线性响应理论，我们研究了这种系统对有序的不稳定性，这是费米表面的一个内在属性。将有序态分为对角态和非对角态，它们分别表示Pomeranchuk不稳定性和库珀配对，而不是原始电子的，而是Bogoliubov粒子（bogolons）的。相应的序参量由原电子的多极矩（对角序参量）和多重态对振幅（非对角序参量）展开，它们是由bogolon序引起的内场引起的.虽然bogolons的序参量部分继承了原始电子的特征，但许多序参量分量以相似的幅度混合。因此，就原始电子而言，相变是对角有序还是非对角有序并没有明确的区别。超导态内部的这些有序不稳定性提供了对在第一转变温度以下具有第二相变的超导体的见解。
It was recently pointed out that Fermi surfaces can remain even in superconductors under symmetric spin-orbit interaction and broken time-reversal symmetry. Using the linear response theory, we study the instability of such systems toward ordering, which is an intrinsic property of Fermi surfaces. The ordered states are classified into diagonal and off-diagonal ones, which respectively indicate the Pomeranchuk instability and Cooper pairing not of original electron but of Bogoliubov particles (bogolons). The corresponding order parameters are expanded by multipole moments (diagonal order parameter) and multiplet pair amplitudes (off-diagonal order parameter) of original electrons, which are induced by the internal fields arising from bogolon ordering. While the bogolons' order parameters partially inherit the characters of the original electrons, many order parameter components mix with similar magnitude. Hence, there is no clear-cut distinction for whether the phase transition is diagonal or off-diagonal ordering in terms of the original electrons. These ordering instabilities inside the superconducting states provide insights into superconductors which have the second phase transition below the first transition temperature.