L. C. Prauchner | Searcharxiv

arXiv2026

Coexistence of superconductivity and charge density wave in a correlated regime

To investigate the coexistence of superconductivity and charge density wave (CDW) in a correlated regime, we employ the Green's functions formalism, as well as the Hubbard-I approximation, as a way to introduce the correlations into the problem, in the form of a repulsive Coulomb interaction $U$. In addition, we investigate the effects of second-nearest neighbor hopping $t_1$ on a pure CDW state. The analysis of the results show that, for small values of $t_1$, both CDW and superconducting gaps compete for the same region on the Fermi surface. The increase of $t_1$ decreases the competition and may lead the system to a coexistence regime. Effects of temperature in the coexistence regime, are also investigated.

cond-mat.supr-con↗

arXiv2019

Effects of a k-dependent Hybridization on the Fermi Surface of an Extended $d-p$ Hubbard Model

The topology of the Fermi surface of an extended $d-p$ Hubbard model is investigated using the Green's function technique in a n-pole approximation. The effects of the $d-p$ hybridization on the Fermi surface are the main focus in the present work. Nevertheless, the effects of doping, Coulomb interaction and hopping to second-nearest-neighbors on the Fermi surface, are also studied. Particularly, it is shown that the crossover from hole-like to electron-like Fermi surface (Lifshitz transition) is deeply affected by the $d-p$ hybridization. Moreover, the pseudogap present in the low doping regime is also affected by the hybridization. The results show that both the doping and the hybridization act in the sense of suppresses the pseudogap. Therefore, the systematic investigation of the Fermi surface topology, shows that not only the doping but also the hybridization can be considered as a control parameter for both the pseudogap and the Lifshitz transition. Assuming that the hybridization is sensitive to external pressure, the present results agree qualitatively with recent experimental data for the cuprate Nd-LSCO.

cond-mat.str-el↗