Kornilovitch P E, Hague J P
Hewlett-Packard Company, Corvallis, OR 97330, USA. Department of Physics, Oregon State University, Corvallis, OR 97331, USA.
J Phys Condens Matter. 2015 Feb 25;27(7):075602. doi: 10.1088/0953-8984/27/7/075602. Epub 2015 Jan 28.
Both FeSe and cuprate superconductors are quasi 2D materials with high transition temperatures and local fermion pairs. Motivated by such systems, we investigate real space pairing of fermions in an anisotropic lattice model with intersite attraction, V, and strong local Coulomb repulsion, U, leading to a determination of the optimal conditions for superconductivity from Bose-Einstein condensation. Our aim is to gain insight as to why high temperature superconductors tend to be quasi 2D. We make both analytically and numerically exact solutions for two body local pairing applicable to intermediate and strong V. We find that the Bose-Einstein condensation temperature of such local pairs pairs is maximal when hopping between layers is intermediate relative to in-plane hopping, indicating that the quasi 2D nature of unconventional superconductors has an important contribution to their high transition temperatures.
铁硒超导体和铜酸盐超导体都是具有高转变温度和局域费米子对的准二维材料。受这类体系的启发，我们研究了一个具有格点间吸引势(V)和强局域库仑排斥势(U)的各向异性晶格模型中费米子的实空间配对，从而根据玻色 - 爱因斯坦凝聚确定超导的最佳条件。我们的目的是深入了解高温超导体为何倾向于准二维。我们针对适用于中等强度和强(V)的两体局域配对给出了解析和数值精确解。我们发现，当层间跳跃相对于面内跳跃为中等时，此类局域对的玻色 - 爱因斯坦凝聚温度最高，这表明非常规超导体的准二维性质对其高转变温度有重要贡献。
