Pair density wave, infinite-length stripes, and holon Wigner crystal in single-band Hubbard model on diagonal square lattice

TL;DR

This study uses advanced DMRG simulations to reveal complex quantum phases, including pair density waves and stripe orders, in the doped Hubbard model on a diagonal square lattice, offering insights into high-temperature superconductivity.

Contribution

First controlled numerical evidence of dominant pair density wave order in the single-band Hubbard model on a diagonal lattice, revealing new quantum phases and charge-spin interactions.

Findings

Identification of three distinct phases: stripe, holon Wigner crystal, and infinite-length stripe.

Observation of a 2D-like pair density wave emerging from short-range superconductivity.

Discovery of long, spanning stripes at higher doping levels.

Abstract

We employ large-scale density-matrix renormalization group (DMRG) simulations to investigate the quantum phase diagram of the hole-doped Hubbard model on square lattices. By implementing a diagonally oriented square lattice and GPU-accelerated DMRG with up to $48000$ states, we identify three distinct quantum phases across $\delta = 5\%$ to $15\%$ doping: (i) A diagonal stripe phase with short-range uniform superconductivity (SC) at lower doping $\delta\lesssim 9\%$; (ii) An intermediate holon Wigner crystal (WC*) phase exhibiting bidirectional charge-density order and short-range SC with spatial oscillating correlations; (iii) An unprecedented infinite-length stripe (i-stripe) phase at $\delta\gtrsim 12\%$ hosting long stripes spanning the whole lattice. Remarkably, as doping increases, the short-range SC in WC* phase evolves into a 2D-like pair density wave (PDW) with divergent susceptibility in the i-stripe phase, constituting probably the first controlled numerical evidence of dominant PDW in the single-band square-lattice Hubbard model. The established 2D-like PDW and its interplay with charge orders provide new perspectives on dynamical layer decoupling phenomena in cuprates and multifaceted relationships between charge, spin and SC orders in quantum materials.