paper

Ground-state phase diagram of the extended two-leg - ladder

arXiv:2211.03778 · doi:10.1103/PhysRevB.107.125114

Abstract

Inspired by the observation of a robust -wave superconducting phase driven by tuning the next-nearest-neighbor (NNN) electron hopping in recent density matrix renormalization group (DMRG) studies of six- and eight-leg - model, we systematically study the phase diagram of the two-leg - ladder with the NNN couplings (including NNN hopping and spin interaction) in a large region of doping level, by means of the DMRG calculations. Upon doping from half filling, we identify the Luther-Emery liquid (LEL) phase, which can be distinguished as the pairing-dominant and charge density-dominant regime by comparing the Luttinger parameter . With the growing NNN couplings, pairing correlations are enhanced and correspondingly increases, driving the system from the density-dominant to the pairing-dominant regime. In the Tomonaga-Luttinger liquid (TLL) phase in the larger doping region, we identify two TLL regimes with different features of charge density correlation. At the quarter filling ( doping level), we find that the strong dimer orders of bond energy in the open system actually decay algebraically and thus do not indicate a spontaneous translational symmetry breaking. Our results show that in the LEL phase of the two-leg ladder, the NNN couplings seem to play the similar role as that on the wider - cylinder, and studies on this more accessible system can be helpful towards understanding the emergence of the remarkable -wave superconducting phase on the wider system.

16 pages, 15 figures

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