Mukherjee Soumya P, Mandal Sudhansu S
Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India.
J Phys Condens Matter. 2009 Sep 16;21(37):375702. doi: 10.1088/0953-8984/21/37/375702. Epub 2009 Aug 19.
Helical edge states exist in the mixed spin singlet and triplet phase of a noncentrosymmetric superconductor (NCSS) when the pair amplitude (PA) in the negative helicity band, Δ(-), is smaller than the PA in the positive helicity band, Δ(+), i.e., when the PA in the triplet component is more than the same in the singlet component. We numerically determine energies of these edge states as a function of γ = Δ(-)/Δ(+). The presence of these edge states is reflected in the tunneling process from a normal metal to an NCSS across a bias energy eV. (i) Angle resolved spin conductance (SC) obeying the symmetry g(s)(φ) = -g(s)(-φ) shows peaks when the bias energy equals the available quasiparticle edge state energy provided [Formula: see text]. (ii) The total SC, G(s), is zero but modulates with eV for finite magnetic field H. (iii) The zero bias peaks of G(s) and total charge conductance, G(c), at finite H split into two at finite eV for moderate H. (iv) At zero bias, G(c) and G(s) increase with H and show peaks at |H|∼γH(0), where H(0) is a characteristic field.
当负螺旋性能带中的配对振幅（PA），即Δ(-)，小于正螺旋性能带中的PA，即Δ(+)时，也就是当三重态分量中的PA大于单重态分量中的PA时，螺旋边缘态存在于非中心对称超导体（NCSS）的混合自旋单重态和三重态相中。我们通过数值计算确定这些边缘态的能量作为γ = Δ(-)/Δ(+)的函数。这些边缘态的存在反映在从正常金属到NCSS跨越偏置能量eV的隧穿过程中。(i) 当偏置能量等于可用的准粒子边缘态能量时，服从对称性g(s)(φ) = -g(s)(-φ)的角分辨自旋电导（SC）会出现峰值，条件是[公式：见原文]。(ii) 总SC，即G(s)，为零，但在有限磁场H下会随eV调制。(iii) 在有限磁场H下，G(s)的零偏置峰值和总电荷电导G(c)在有限eV时，对于中等磁场H会分裂为两个。(iv) 在零偏置时，G(c)和G(s)随H增加，并在|H|∼γH(0)处出现峰值，其中H(0)是一个特征场。
