Spin Texture in Doped Mott Insulators with Spin-Orbit Coupling

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 weak Rashba spin-orbit coupling (SOC). It is described by an emergent angular momentum Jz = ±3/2 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 with 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. CONTENTSA. Sign structures in the t-J and σ•t-J models 10 B. One-hole wave function ansatz and emergent symmetry in the t-J model 10 C. Rashba interaction 11 1. Total angular momentum J z 11 2. ED under periodic boundary condition 12 D. Variational Monte Carlo procedure 13 1. Variational ground state at half-filling 13 2. Variational wave functions for the t-J-R model 13 E. Spin-polarized spectral function 14 F. Fragility of spin texture in a Fermi Liquid 14 References 15