On the theory of two-dimensional nematic superconductivity: Rectangular lattice.

In this work, we derive equations for the superconducting nematic order parameter, critical temperature, and chemical potential for two-dimensional rectangular lattice by taking into account nearest- and next-nearest-neighbor hopping of carriers (electrons or holes). By solving the obtained equations, we have found that the symmetry of the order parameter and other superconducting properties strongly depend on the sign and the magnitude of the next-nearest neighbor hopping and on doping. We have analyzed the possible crossover of the system from the Bose–Einstein condensation to the Bardeen–Cooper–Schrieffer superconductivity regimes with increasing the electron density. As we show, the crossover, which can be tuned by both doping and nearest neighbor hopping, only occurs in the s-channel at physically meaningful values of these parameters. A possible connection of the obtained results to the properties of doped high-temperature cuprate superconductors is discussed. [ABSTRACT FROM AUTHOR]