Dynamic charge Kondo effect and a slave fermion approach to the Mott transition

TL;DR

This paper introduces a novel slave fermion approach to study the Mott transition, revealing a dynamic charge Kondo effect and critical scaling behavior, and providing insights into the nature of the transition in strongly correlated systems.

Contribution

The work proposes a new slave fermion algorithm for the Mott transition, capturing key features like the charge Kondo effect and phase diagram, extending understanding of strongly correlated electron systems.

Findings

Identifies a continuous Mott transition at finite U in the Hubbard model.

Reveals a dynamic charge Kondo effect involving doublon and holon states.

Shows the transition is suppressed to U=0 with intersite antiferromagnetic correlations.

Abstract

Mott transition plays a key role in strongly correlated physics but its nature is not yet fully understood. Motivated by recent development of Schwinger boson approach for the Kondo lattice, we propose in this work a novel slave fermion algorithm to study the Mott transition. Upon local approximation, our method yields a phase diagram with a zero-temperature continuous (Mott) metal-insulator transition at finite Coulomb interaction $U$ for the half-filled one-band Hubbard model on a square lattice, and the resistivity exhibits a critical scaling around the quantum Widom line. We argue that the Mott transition may be associated with a dynamic charge Kondo effect of local degenerate doublon and holon states, causing sharp resonances on the doublon/holon and electron spectra. The transition is pushed to $U=0$ once intersite antiferromagnetic correlations are included, in agreement with exact numerical calculations. Our approach captures some essential features of the Mott transition and offers an alternative angle to view this important problem. It can be extended to study other correlated electron models with more complicated local interactions.