论文标题

单层$β$ -bi $ _ {2} $ pd中超导性和拓扑方面的预测

Prediction of superconductivity and topological aspects in single-layer $β$-Bi$_{2}$Pd

论文作者

Liu, Peng-Fei, Li, Jingyu, Tu, Xin-Hai, Yin, Huabing, Sa, Baisheng, Zhang, Junrong, Singh, David J., Wang, Bao-Tian

论文摘要

拓扑超导体的特征是居住在超导差距中的拓扑非平凡状态,是最近发现的具有Majorana fermions的材料类。超导性和拓扑状态的相互作用带来了在冷凝物质系统中实现此类拓扑超导体的机会。到目前为止,理论上已经预测并通过实验证实了这种形式的几个单物质拓扑超导体。在这里,使用第一原理计算,我们研究了超导单层$β$ -bi $ _ {2} $ pd。该单层的Fermi水平附近的状态的电子密度以Bi-P和PD-D轨道为主导,形成了带有多级床单的两波段费米表面。与电子敏感性合作,软声声子带的存在是单层$β$ -bi $ _ {2} $ pd的电子 - 音波超导性的。借助中心对称结构,单层$β$ -bi $ _ {2} $ pd在整个布里群区域上具有连续的差距,并且在其一维边界处具有类似拓扑的狄拉克状状态。目前的发现将导致对一维拓扑超导性的期望,而Majorana绑定了$β$ -Bi $ _ {2} $ PD的单层候选者,并具有内在的全间隙超导性。

Topological superconductors, characterized by topologically nontrivial states residing in a superconducting gap, are a recently discovered class of materials having Majorana Fermions. The interplay of superconductivity and topological states give rise to opportunities for achieving such topological superconductors in condensed matter systems. Up to now, several single-material topological superconductors in this form have been theoretically predicted and experimentally confirmed. Here, using the first-principles calculations, we study the superconducting single-layer $β$-Bi$_{2}$Pd. The electronic density of states near Fermi level of this monolayer are dominated by the Bi-p and Pd-d orbitals, forming a two-band Fermi surface with multi-class sheets. The presence of soft phonon bands, in cooperation with the electron susceptibility, account for electron-phonon superconductivity of single-layer $β$-Bi$_{2}$Pd. With the centrosymmetric structure, single-layer $β$-Bi$_{2}$Pd possesses a continuous gap over the whole Brillouin zone and topological Dirac-like states at its one-dimensional boundary. The present findings would lead to the expectation of one-dimensional topological superconductivity and Majorana bound states in monolayer candidate of $β$-Bi$_{2}$Pd with intrinsic full-gap superconductivity.

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