On the correct formula for the lifetime broadened superconducting density of states
On the correct formula for the lifetime broadened superconducting density of states
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DOI：
10.1088/0953-8984/20/01/015215
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发表时间：
2008-01-09
影响因子：
2.7
通讯作者：
Rozema, Lee A.
中科院分区：
文献类型：
--
作者：
Mitrovic, Bozidar;Rozema, Lee A.
我们认为著名的Dynes公式(Dynes et al 1978 Phys。Rev. Lett. 41 1509)的超导准粒子态密度，它试图以一种近似的方式结合寿命的扩大，不能在微观上证明常规超导体。相反，我们提出了一个新的简单公式，其中能量间隙具有有限的虚部-Delta(2)，准粒子能量是实的。我们证明了在准粒子近似中，2 δ(2)给出了常规超导体在间隙边缘的准粒子衰减率。这个结论并不取决于引起准粒子衰变的相互作用的性质。在强耦合超导体Pb0.9Bi0.1的情况下对新公式进行了验证，结果与理论预测非常吻合。虽然Dynes公式和本文提出的公式都给出了Pb0.9Bi0.1的良好拟合和拟合参数，但只有后者的公式在微观上是合理的。
We argue that the well known Dynes formula (Dynes et al 1978 Phys. Rev. Lett. 41 1509) for the superconducting quasiparticle density of states, which tries to incorporate the lifetime broadening in an approximate way, cannot be justified microscopically for conventional superconductors. Instead, we propose a new simple formula in which the energy gap has a finite imaginary part -Delta(2) and the quasiparticle energy is real. We prove that in the quasiparticle approximation 2 Delta(2) gives the quasiparticle decay rate at the gap edge for conventional superconductors. This conclusion does not depend on the nature of interactions that cause the quasiparticle decay. The new formula is tested on the case of a strong coupling superconductor Pb0.9Bi0.1 and an excellent agreement with theoretical predictions is obtained. While both the Dynes formula and the one proposed in this work give good fits and fit parameters for Pb0.9Bi0.1, only the latter formula can be justified microscopically.