Stripe order in the underdoped region of the two-dimensional Hubbard model

TL;DR

This paper uses advanced numerical methods to identify a stripe order in the underdoped region of the two-dimensional Hubbard model, revealing complex inhomogeneous orderings relevant to high-temperature superconductors.

Contribution

It uncovers a stripe order with fluctuating wavelength in the underdoped Hubbard model, demonstrating the effectiveness of modern numerical techniques in solving complex microscopic models.

Findings

Discovery of a highly compressible stripe order in the model

Stripe wavelength fluctuations are coupled to pairing order

Favored stripe order differs from experimental observations

Abstract

Competing inhomogeneous orders are a central feature of correlated electron materials including the high-temperature superconductors. The two- dimensional Hubbard model serves as the canonical microscopic physical model for such systems. Multiple orders have been proposed in the underdoped part of the phase diagram, which corresponds to a regime of maximum numerical difficulty. By combining the latest numerical methods in exhaustive simulations, we uncover the ordering in the underdoped ground state. We find a stripe order that has a highly compressible wavelength on an energy scale of a few Kelvin, with wavelength fluctuations coupled to pairing order. The favored filled stripe order is different from that seen in real materials. Our results demonstrate the power of modern numerical methods to solve microscopic models even in challenging settings.