Impurity-induced quasiparticle transport and universal-limit Wiedemann-Franz violation in d-wave superconductors
Impurity-induced quasiparticle transport and universal-limit Wiedemann-Franz violation in d-wave superconductors
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DOI：
10.1103/physrevb.62.1270
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发表时间：
1999-08
影响因子：
3.7
通讯作者：
A. Durst;Patrick A. Lee
中科院分区：
文献类型：
--
作者：
A. Durst;Patrick A. Lee
由于 d 波超导体中间隙的节点结构，杂质的存在会在零温度下产生有限密度的准粒子激发。由于这些杂质引起的准粒子都是由杂质产生和散射的，因此先前的计算表明存在一个通用极限 $(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Omega}}0,$ $$\stackrel{\ensuremath{\rightarrow}}{T}0)$，其中传输系数获得与散射无关的值，仅取决于速度各向异性 ${v}_{f}{/v}_{2}。$ 我们改进了先前的结果，包括顶点校正和费米液体校正在我们的通用极限电导率、热导率和自旋电导率的计算中的贡献。我们发现，虽然顶点校正修改了电导率，而费米液体校正重新规范了电导率和自旋电导率，但只有热导率保持其通用值，与杂质散射或费米液体相互作用无关。因此，低温热导率测量提供了获得高${T}_{c}$铜酸盐超导体速度各向异性的最直接方法。
Due to the node structure of the gap in a d-wave superconductor, the presence of impurities generates a finite density of quasiparticle excitations at zero temperature. Since these impurity-induced quasiparticles are both generated and scattered by impurities, prior calculations indicate a universal limit $(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Omega}}0,$ $\stackrel{\ensuremath{\rightarrow}}{T}0)$ where the transport coefficients obtain scattering-independent values, depending only on the velocity anisotropy ${v}_{f}{/v}_{2}.$ We improve upon prior results, including the contributions of vertex corrections and Fermi-liquid corrections in our calculations of universal-limit electrical, thermal, and spin conductivity. We find that while vertex corrections modify electrical conductivity and Fermi-liquid corrections renormalize both electrical and spin conductivity, only thermal conductivity maintains its universal value, independent of impurity scattering or Fermi-liquid interactions. Hence, low-temperature thermal conductivity measurements provide the most direct means of obtaining the velocity anisotropy for high-${T}_{c}$ cuprate superconductors.