Intrinsic surface superconducting instability in type-I Weyl semimetals
Intrinsic surface superconducting instability in type-I Weyl semimetals
复制标题
DOI：
10.1103/physrevb.108.165144
复制
发表时间：
2023-04
影响因子：
3.7
通讯作者：
Aymen Nomani;P. Hosur
中科院分区：
文献类型：
--
作者：
Aymen Nomani;P. Hosur
最近对非磁性Weyl半金属的实验发现，Weyl半金属的体和表面超导性是分开的，这就提出了一个问题，即当体保持正常状态时，表面费米弧是否能支持内在超导性。由于费米弧在端点处与体态合并，因此缺乏定义良好的表面哈密顿量，阻碍了对这个问题的理论回答。在一个可以产生任意费米弧的现象学模型上使用另一种基于格林函数的方法，我们表明——在平均场理论中——表面可以支持标准的库珀不稳定性，而整体仍然是无序的。尽管表面具有较低的维数，但与体相比，较高的态密度使其具有较高的平均场超导转变温度。
Recent experiments on non-magnetic Weyl semimetals have seen separate bulk and surface superconductivity in Weyl semimetals, which raises the question of whether the surface Fermi arcs can support intrinsic superconductivity while the bulk stays in the normal state. A theoretical answer to this question is hindered by the absence of a well-defined surface Hamiltonian since the Fermi arcs merge with the bulk states at their endpoints. Using an alternate, Green's functions-based approach on a phenomenological model that can yield arbitrary Fermi arcs, we show -- within mean-field theory -- that the surface can support a standard Cooper instability while the bulk remains disordered. Although the surface has lower dimensionality, a higher density of states compared to the bulk allows it to have a higher mean-field superconducting transition temperature.