Zeeman磁场对有节点非常规超导体节点结构的影响（英文）

Influence of Zeeman magnetic field on the nodal structure of unconventional superconductors

在大部分非常规超导体中,准粒子激发谱中存在着"线节点"或"点节点"。这些节点的存在,导致热力学量和输运系数在低温区的温度变化呈现幂次律。解析分析表明,外加的弱Zeeman磁场会显著影响节点的结构。尤其是,预言在某些情况下Zeeman磁场可能在费米面上诱导出"面节点"。计算若干自旋单态和自旋三重态的电子比热,结果显示外加的弱Zeeman磁场对节点结构的影响会导致幂次律产生巨大变化。

In most of the unconventional superconductors, the quasiparticle excitation spectrum possesses line or point nodes leading to a power-law temperature dependence in the thermodynamic quantities and transport coefficients at low temperatures. In this work we show analytically that an applied weak Zeeman magnetic field can drastically alter these nodal structures. In particular, we predict that surface nodes might be induced on the Fermi surface under certain circumstances. Our numerical calculations of electronic specific heat for selected spin-singlet and spin-triplet states confirm that the change in the nodal structure may accompany significant modification in the power- law temperature dependence.