arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2004.10217cond-mat.supr-concond-mat.str-el
收藏

轨道间散射对掺杂Dirac材料超导电性的影响

The effect of interorbital scattering on superconductivity in doped Dirac materials

David Dentelski, Vladyslav Kozii, Jonathan Ruhman

摘要:

非常规超导性已在各种掺杂材料中发现,包括拓扑绝缘体、半金属和扭曲双层。这些系统的一个统一的属性是强轨道杂化,这涉及到配对的状态与非平凡的布洛赫波函数。与天真的期望相反,这些超导体中的许多对无序具有相对的弹性。在这里,我们研究了掺杂的3D狄拉克系统中的超导电性的一般无序的影响,作为一个典型的例子附近的带交叉点的色散。我们认为,由于强轨道杂化,轨道间散射过程是自然存在的,必须考虑到。我们用Abrikosov-Gor'kov理论计算了各种对态和散射通道的临界温度的降低。通过这种方式,无序的作用被单个参数$Γ$(对散射率)捕获。这个过程是非常普遍的,可以很容易地应用到不同的能带结构和无序配置。我们的研究结果表明,轨道间散射对超导性有显着的影响,其中不同的配对状态的鲁棒性高度依赖于不同的轨道间散射通道的相对强度。我们的分析还揭示了一个保护,类似于安德森定理,奇宇称配对状态与总角动量为零(B相的超流$^3$他)。这种奇对状态是在$\mathcal{CT}$对称性(而不是标准安德森理论中的$\mathcal{T}$对称性)下的伙伴单线态,其中$\mathcal{C}$和$\mathcal{T}$分别是手性和时间反演对称性。因此,它被保护免受任何遵守$\mathcal{CT}$对称性的无序势的影响,其中包括一系列时间反转奇(磁)杂质。

英文摘要:

Unconventional superconductivity has been discovered in a variety of doped materials, including topological insulators, semimetals and twisted bilayers. A unifying property of these systems is strong orbital hybridization, which involves pairing of states with non-trivial Bloch wave functions. In contrast to naive expectation, many of these superconductors are relatively resilient to disorder. Here we study the effects of a generic disorder on superconductivity in doped 3D Dirac systems, which serve as a paradigmatic example for the dispersion near a band crossing point. We argue that due to strong orbital hybridization, interorbital scattering processes are naturally present and must be taken into account. We calculate the reduction of the critical temperature for a variety of pairing states and scattering channels using Abrikosov-Gor'kov theory. In that way, the role of disorder is captured by a single parameter $Γ$, the pair scattering rate. This procedure is very general and can be readily applied to different band structures and disorder configurations. Our results show that interorbital scattering has a significant effect on superconductivity, where the robustness of different pairing states highly depends on the relative strength of the different interorbital scattering channels. Our analysis also reveals a protection, analogous to the Anderson's theorem, of the odd-parity pairing state with total angular momentum zero (the B-phase of superfluid $^3$He). This odd-pairty state is a singlet of partners under $\mathcal{CT}$ symmetry (rather than $\mathcal{T}$ symmetry in the standard Anderson's theory), where $\mathcal{C}$ and $\mathcal{T}$ are chiral and time-reversal symmetries, respectively. As a result, it is protected against any disorder potential that respects $\mathcal{CT}$ symmetry, which includes a family of time-reversal odd (magnetic) impurities.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑