Pseudogap and Fermi-arc Evolution in the Phase-fluctuation Scenario

TL;DR

This study investigates the evolution of pseudogaps and Fermi arcs in underdoped cuprates using phase fluctuation simulations, revealing how spectral properties change with temperature and vortex excitations.

Contribution

It introduces a numerical method combining Monte Carlo sampling with Chebyshev polynomial techniques to analyze spectral functions without diagonalization.

Findings

Energy gap maintains d-wave symmetry below T_KT

Fermi arcs abruptly appear above T_KT

Arc length correlates with vortex excitations

Abstract

Pseudogap phenomena and the formation of Fermi arcs in underdoped cuprates are numerically studied in the presence of phase fluctuations that are simulated by an XY model. Most importantly the spectral function for each Monte Carlo sample is calculated directly and efficiently by the Chebyshev polynomials without having to diagonalize the fermion Hamiltonian, which enables us to handle a system large enough to achieve sufficient momentum/energy resolution. We find that the momentum dependence of the energy gap is identical to that of a pure d-wave superconductor well below the KT-transition temperature ($T_{KT}$), while displays an upturn deviation from $\cos k_x - \cos k_y$ with increasing temperature. An abrupt onset of the Fermi arcs is observed above $T_{KT}$ and the arc length exhibits a similar temperature dependence to the thermally activated vortex excitations.