Spin Texture in Doped Mott Insulators with Spin-Orbit Coupling

TL;DR

This paper demonstrates that a spin texture associated with a hole in a doped Mott insulator with weak Rashba spin-orbit coupling can be explicitly observed, revealing an emergent angular momentum and extending deep into the Brillouin zone.

Contribution

It shows that spin textures due to SOC can be explicitly manifested in doped Mott insulators, supported by exact diagonalization and variational Monte Carlo calculations.

Findings

Spin texture characterized by emergent angular momentum J_z=±3/2.

Spin texture extends deep inside the Brillouin zone.

Spin texture can be probed by spin-polarized ARPES.

Abstract

A hole injected into a Mott insulator will gain an internal structure as recently identified by exact numerics, which is characterized by a nontrivial quantum number whose nature is of central importance in understanding the Mott physics. In this work, we show that a spin texture associated with such an internal degree of freedom can explicitly manifest after the spin degeneracy is lifted by a \emph{weak} Rashba spin-orbit coupling (SOC). It is described by an emergent angular momentum $J_{z}=\pm3/2$ as shown by both exact diagonalization (ED) and variational Monte Carlo (VMC) calculations, which are in good agreement with each other at a finite size. In particular, as the internal structure such a spin texture is generally present in the hole composite even at high excited energies, such that a corresponding texture in momentum space, extending deep inside the Brillouin zone, can be directly probed by the spin-polarized angle-resolved photoemission spectroscopy (ARPES). This is in contrast to a Landau quasiparticle under the SOC, in which the spin texture induced by SOC will not be protected once the excited energy is larger than the weak SOC coupling strength, away from the Fermi energy. We point out that the spin texture due to the SOC should be monotonically enhanced 1with reducing spin-spin correlation length in the superconducting/pseudogap phase at finite doping. A brief discussion of a recent experiment of the spin-polarized ARPES will be made.