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arXiv 2212.07445cond-mat.supr-con
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单层和少层石墨烯中的超导性:III杂质诱导的亚能隙态和准粒子干涉图样

Superconductivity in monolayer and few-layer graphene: III Impurity-induced subgap states and quasi-particle interference patterns

Emile Pangburn, Louis Haurie, Adeline Crépieux, Oladunjoye A. Awoga, Nicholas Sedlmayr, Annica M. Black-Schaffer, Catherine Pépin, Cristina Bena

摘要:

我们考虑了单层和少层石墨烯中能量最有利的自旋单重态和自旋三重态超导配对对称性,并计算了标量或磁性杂质存在下的能谱。我们发现,除了自旋单重态$s$波态外,对于所有类型的配对,标量杂质都存在两个双简并亚带隙态。对于磁性杂质,根据序参量对称性,可以形成两个或四个亚能隙态。我们发现,这些状态的自旋极化允许区分自旋单重态和三重态配对,例如,只有自旋三重态显示具有相同自旋的相反能量的子带隙态。我们还计算了准粒子干涉图案与subgap状态,并发现它们表现出的功能,可以区分不同类型的配对对称性,特别是打破旋转对称性的节点状态,更强的自旋单线态$d_{xy}$和$d_{x^2-y^2}$比自旋三线态$p_x$和$p_y$状态。

英文摘要:

We consider the most energetically favorable symmetry-allowed spin-singlet and spin-triplet superconducting pairing symmetries in monolayer and few-layer graphene, and for each calculate the energy spectrum in the presence of a scalar or magnetic impurity. We find that two doubly degenerate subgap states exist for scalar impurities for all types of pairing, except for the spin-singlet $s$-wave state. For magnetic impurities, two or four subgap states may form depending on the order parameter symmetry. We find that the spin polarization of these states allows one to distinguish between spin-singlet and triplet pairing, for example, only the spin-triplet states show opposite-energy subgap states with the same spin. We also calculate the quasi-particle interference patterns associated with the subgap states and find that they exhibit features that could distinguish between different types of pairing symmetries, especially a breaking of rotational symmetry for nodal states, stronger for the spin-singlet $d_{xy}$ and $d_{x^2-y^2}$ than for the spin-triplet $p_x$ and $p_y$ states.

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。

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