Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 38: Superconductivity: Theory
TT 38.6: Vortrag
Freitag, 9. September 2022, 10:45–11:00, H23
Groundstate phase diagrams of variants of the two-leg t-J ladder at low fillings — •Steffen Bollmann1,2, Alexander Osterkorn2, Elio König1, and Salvatore R. Manmana2 — 1Max-Planck Institute for Solid State Research, 70569 Stuttgart, Germany — 2Institut for Theoretical Physics, Georg-August-University Göttingen, 37077 Göttingen, Germany
We study variants of the two-leg t-J ladder at low fillings using matrix product states (MPS) and perturbative approaches. While the groundstate phase diagram for the usual t-J ladder with spatially isotropic couplings at fillings n>0.5 has been studied in detail, relatively little is known at low fillings. We address the phase diagram at these low fillings and investigate the influence of nearest-neighbor Coulomb interactions V and asymmetries in the spin-exchange Jz ≠ Jx = Jy on the size and nature of superconducting phases. For V=0 the superconducting phase is enhanced, and we find a crossover within this phase from s-wave pairing to d-wave pairing when increasing the filling. For Jz=0, the size of the superconducting region is reduced. In this talk, I will present the phase diagrams, discuss the physics, briefly introduce the methods used to classify the different phases, and give an outlook to possible realizations in experiments.