We consider a model for superconductivity in a two-band superconductor, having an anisotropic electronic structure made of two partially overlapping bands with a first hole-like and a second electron-like fermi surface. In this pairing scenario, driven by the interplay between interband $V_{i,j}$ and intraband $V_{i,i}$ pairing terms, we have solved the two gap equations at the critical temperature $T = T_c$ and calculate $T_c$ and the chemical potential $μ$ as a function of the number of carriers $n$ for various values of pairing interactions, $V_{1,1}$, $V_{2,2}$, and $V_{1,2}$. The results show the complexity of the physics of condensates with multiple order parameters with the chemical potential near band edges.
Interband pairing as the origin of the sublattice dichotomy in monolayer FeSe/SrTiO_3
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；School of Physics, Beijing Institute of Technology（北京理工大学物理学院）；Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences（中国科学院大学 Kavli理论科学研究所）；New Cornerstone Science Laboratory（新基石科学实验室）
Specific heat of Ca$_{0.32}$Na$_{0.68}$Fe$_2$As$_2$ single crystals: unconventional s$_\pm$ multi-band superconductivity with intermediate repulsive interband coupling and sizable attractive intraband couplings
报道了高质量重空穴掺杂超导体Ca $_{0.32}$ Na $_{0.68}$ Fe $_2$ As $_2$单晶的低温比热研究。该化合物表现出体超导性，转变温度为$T_c \approx 34$ \，K，这是明显的从磁化，运输，和比热测量。零场数据表明，在正常状态下的索末菲系数$γ\approx 53$ mJ/mol K $^{2}$的显着的电子比热。使用多带Eliashberg分析，我们证明了在超导状态下的零场比热的依赖性是很好地描述了一个三带模型与非常规的s $_\pm$配对对称性和间隙幅度$Δ_i$约为2.35，7.48，和-7.50 meV。我们的分析表明，一个不可忽视的吸引力带内耦合，这有助于显着相对较高的$T_c$值。费米表面平均的排斥和吸引耦合强度是可比的大小和外部的强耦合限制经常采用描述高$T_c$铁磷属元素化物超导体。我们进一步推断总质量重整化的顺序为5，包括相关性和电子玻色子相互作用的影响。
Coexistence of giant Cooper pairs with a bosonic condensate and anomalous behavior of energy gaps in the BCS-BEC crossover of a two-band superfluid Fermi gas
Topological flat bands, valley polarization, and interband superconductivity in magic-angle twisted bilayer graphene with proximitized spin-orbit couplings
