Evolution of the single-hole spectral function across a quantum phase transition in the anisotropic-triangular-lattice antiferromagnet

TL;DR

This paper investigates how the single-hole spectral function evolves across a quantum phase transition in an anisotropic triangular antiferromagnet, using a large-N approach to connect magnetically-ordered and spin-liquid states.

Contribution

It introduces a unified large-N framework to study the spectral function across a quantum phase transition in a frustrated magnet.

Findings

Spectral function shows distinct features in ordered and spin-liquid phases.

Transition affects the quasiparticle coherence and spectral weight distribution.

Results have implications for ARPES experiments on frustrated magnets like Cs$_2$CuCl$_4$.

Abstract

We study the evolution of the single-hole spectral function when the ground state of the anisotropic-triangular-lattice antiferromagnet changes from the incommensurate magnetically-ordered phase to the spin-liquid state. In order to describe both of the ground states on equal footing, we use the large-N approach where the transition between these two phases can be obtained by controlling the quantum fluctuations via an 'effective' spin magnitude. Adding a hole into these ground states is described by a t-J type model in the slave-fermion representation. Implications of our results to possible future ARPES experiments on insulating frustrated magnets, especially Cs$_2$CuCl$_4$, are discussed.