Superconductivity near a quantum critical point in the extreme retardation regime
Superconductivity near a quantum critical point in the extreme retardation regime
复制标题
极端延迟状态下接近量子临界点的超导性
作者：
E. Yuzbashyan;M. Kiessling;B. Altshuler
我们研究了具有极慢相互作用的量子临界费米子，形式为V(ωL)=(g/|ωL|)γ，其中ωL是转移的松原频率。在临界温度T=TC下，该体系经历了正常-超导体相变。序参数是如在埃利亚斯堡理论中那样的依赖于频率的间隙函数∆(ωn)。一般来说，γ(Cid：29)1的相互作用是非常迟缓的，除非在低温下γ和Gt；3是完全fi的。我们计算了正常态能级fic热、能级fic热、能级跃迁∆(ωn)和朗道自由能。我们的解在极限γ→∞中是渐近精确的。在低温下，我们证明了自由能的整体极小值是非简并的，并确定了序参数、自由能和比fi_c热。这些答案适用于T→0和γ>；3。我们还发现并研究了γ模型的一个不稳定性：在T_fi_0和略高于T_c处的负→_c热。
We study fermions at quantum criticality with extremely retarded interactions of the form V ( ω l ) = ( g/ | ω l | ) γ , where ω l is the transferred Matsubara frequency. This system undergoes a normal-superconductor phase transition at a critical temperature T = T c . The order parameter is the frequency-dependent gap function ∆( ω n ) as in the Eliashberg theory. In general, the interaction is extremely retarded for γ (cid:29) 1 , except at low temperatures γ > 3 is sufficient. We evaluate the normal state specific heat, T c , the jump in the specific heat, ∆( ω n ) near T c , and the Landau free energy. Our answers are asymptotically exact in the limit γ → ∞ . At low temperatures, we prove that the global minimum of the free energy is nondegenerate and determine the order parameter, the free energy, and the specific heat. These answers are exact for T → 0 and γ > 3 . We also uncover and investigate an instability of the γ model: negative specific heat at T → 0 and just above T c .
影响因子：
3
作者：
Chubukov, Andrey, V;Abanov, Artem;Wu, Yi-Ming
通讯作者：
Wu, Yi-Ming