论文标题
Cu掺杂的BI $ _2 $ SE $ _3 $具有潜在障碍的超导性
Superconductivity in Cu-doped Bi$_2$Se$_3$ with potential disorder
论文作者
论文摘要
我们研究了随机非磁性杂质对Cu掺杂的BI $ _2 $ SE $ _3 $中超导过渡温度$ T_C $的影响，为此提出了四种类型的配对电位。尽管所有候选人都属于$ s $波的对称性，但电子结构中的两个轨道自由度丰富了库珀对的对称性品种，例如均匀的轨道 - 差异和奇异的轨道。我们通过在六角形晶格上使用紧密结合的哈密顿量来考虑Cu掺杂的BI $ _2 $ SE $ _3 $的现实电子结构，并通过天生的近似中绿色功能的自我能源来考虑杂质散射的效果。我们发现，即使存在杂质，均匀的 - 骨值旋转旋转超导也基本上是稳健的。鲁棒性的程度取决于正常状态中的电子结构和轨道空间中的配对对称性。另一方面，在存在潜在障碍的情况下，两个奇怪的神经三键级参数总是很脆弱。
We study the effects of random nonmagnetic impurities on superconducting transition temperature $T_c$ in a Cu-doped Bi$_2$Se$_3$, for which four types of pair potentials have been proposed. Although all the candidates belong to $s$-wave symmetry, two orbital degree of freedom in electronic structures enriches the symmetry variety of a Cooper pair such as even-orbital-parity and odd-orbital-parity. We consider realistic electronic structures of Cu-doped Bi$_2$Se$_3$ by using tight-binding Hamiltonian on a hexagonal lattice and consider effects of impurity scatterings through the self-energy of the Green's function within the Born approximation. We find that even-orbital-parity spin-singlet superconductivity is basically robust even in the presence of impurities. The degree of the robustness depends on the electronic structures in the normal state and on the pairing symmetry in orbital space. On the other hand, two odd-orbital-parity spin-triplet order parameters are always fragile in the presence of potential disorder.
