Proposal for asymmetric photoemission and tunneling spectroscopies in quantum simulators of the triangular-lattice Fermi-Hubbard model

TL;DR

This paper predicts asymmetric photoemission and tunneling spectroscopies in quantum simulators of the triangular-lattice Fermi-Hubbard model, revealing two types of magnetic polarons and the effects of doping on spin-charge interplay.

Contribution

It introduces theoretical predictions of asymmetric spectroscopic responses and magnetic polarons in doped triangular Mott antiferromagnets, guiding future experimental verification.

Findings

Identification of lightly and heavily renormalized quasiparticles with distinct momentum and band characteristics.

Prediction of asymmetric spectral functions and density of states in doped triangular Mott insulators.

Demonstration of the significant role of spin-charge interplay in doped frustrated systems.

Abstract

Recent realization of well-controlled quantum simulators of the triangular-lattice Fermi-Hubbard model, including the triangular optical lattices loaded with ultracold Fermions and the heterostructures of the transition-metal dichalcogenides, as well as the more advanced techniques to probe them, pave the way for studying frustrated Fermi-Hubbard physics. Here, we theoretically predict asymmetric photoemission and tunneling spectroscopies for a lightly hole-doped and electron-doped triangular Mott antiferromagnet, and reveal two distinct types of magnetic polarons: a \emph{lightly} renormalized quasiparticle with the same momentum as the spin background and a \emph{heavily} renormalized quasiparticle with a shifted momentum and a nearly flat band, using both analytical and unbiased numerical methods. We propose these theoretical findings to be verified in frustrated optical lattices and Moir\'e superlattices by probing various observables including the spectral function, the density of states, the energy dispersion and the quasiparticle weight. Moreover, we reveal the asymmetric response of the spin background against charge doping, demonstrating that the interplay between the local spin and charge degrees of freedom plays a vital role in doped triangular Mott antiferromagnets.