# Correlation effects on the magnetization process of the Kitaev model

## TL;DR

This study uses variational Monte Carlo to explore how magnetic fields influence the phase transitions and intermediate states in the Kitaev honeycomb model, revealing different behaviors for ferromagnetic and antiferromagnetic couplings.

## Contribution

It introduces a generalized BCS wave function with Jastrow factors to accurately describe the ground state and uncovers the existence of an intermediate phase in the antiferromagnetic case.

## Key findings

- Two phase transitions for antiferromagnetic coupling.
- One phase transition for ferromagnetic coupling.
- Stable intermediate state in the antiferromagnetic case.

## Abstract

By using the variational Monte Carlo method, we study the magnetization process of the Kitaev honeycomb model in a magnetic field. Our trial wavefunction is a generalized Bardeen-Cooper-Schrieffer wave function with the Jastrow correlation factor, which exactly describes the ground state of the Kitaev model at zero magnetic field using the Jordan-Wigner (JW) transformation. We find that two phase transitions occur for the antiferromagnetic Kitaev coupling, while only one phase transition occurs for the ferromagnetic Kitaev coupling. For the antiferromagnetic Kitaev coupling, we also find that the topology of the momentum distribution of the JW fermions changes at the transition point from the Kitaev spin liquid to an intermediate state. Our numerical results indicate that the intermediate state between the Kitaev spin liquid and the fully polarized phases stably exists in the bulk system on two dimensions for the antiferromagnetic Kitaev coupling against many-body correlations.