Ferroelectricity-induced multiorbital odd-frequency superconductivity in SrTiO3
Ferroelectricity-induced multiorbital odd-frequency superconductivity in SrTiO3
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DOI：
10.1103/physrevb.102.184506
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发表时间：
2020-11-10
影响因子：
3.7
通讯作者：
Yanase, Youichi
中科院分区：
文献类型：
--
作者：
Kanasugi, Shota;Kuzmanovski, Dushko;Yanase, Youichi
我们表明，SrTiO 3可以是一个平台，用于观察体奇频超导态，由于其多轨道/多频带的性质。我们考虑了SrTiO_3在铁电临界点附近的三轨道紧束缚模型。假设一个轨道内自旋单态s波超导序参量，它示出的奇频率对关联产生由于固有的LS耦合，导致本地轨道混合。此外，我们发现存在额外的奇频率对相关的铁电相，这是由一个奇宇称轨道杂化项成比例的铁电序参数。我们还进行了群论分类的奇频对振幅的基础上的费米子和空间群对称性的系统。分类表使我们能够预测的奇频对相关性的基础上，我们考虑到正常状态的哈密尔顿的对称性的主导成分。此外，我们表明，实验签名的奇宇称轨道杂化，这是铁电性引起的奇频率对相关性的一个重要组成部分，可以观察到的谱函数和态密度。
We demonstrate that SrTiO3 can be a platform for observing the bulk odd-frequency superconducting state owing to its multiorbital/multiband nature. We consider a three-orbital tight-binding model for SrTiO3 in the vicinity of a ferroelectric critical point. Assuming an intraorbital spin-singlet s-wave superconducting order parameter, it is shown that the odd-frequency pair correlations are generated due to the intrinsic LS coupling which leads to local orbital mixing. Furthermore, we show the existence of additional odd-frequency pair correlations in the ferroelectric phase, which is induced by an odd-parity orbital hybridization term proportional to the ferroelectric order parameter. We also perform a group theoretical classification of the odd-frequency pair amplitudes based on the fermionic and space group symmetries of the system. The classification table enables us to predict the dominant components of the odd-frequency pair correlations based on the symmetry of the normal state Hamiltonian that we take into account. Furthermore, we show that experimental signatures of odd-parity orbital hybridization, which is an essential ingredient for ferroelectricity-induced odd-frequency pair correlations, can be observed in the spectral functions and density of states.