Doublon-like excitations and their phononic coupling in a Mott charge-density-wave system

TL;DR

This study observes narrow electronic excitations in 1T-TaS2 that couple strongly to phonons, providing microscopic insights into the interplay between Mott insulating states and charge density wave lattice dynamics.

Contribution

It reveals the coupling between doublon-like excitations and phonons in a Mott charge-density-wave system, offering new microscopic understanding of their interaction.

Findings

Narrow electronic excitations couple to amplitude mode phonons.

Observation of interplay between Mott state excitations and lattice dynamics.

Microscopic view of electron-phonon coupling in a charge density wave system.

Abstract

Electron-phonon-driven charge density waves can in some circumstances allow electronic correlations to become predominant, driving a system into a Mott insulating state. New insights into both the Mott state and preceding charge density wave may result from observations of the coupled dynamics of their underlying degrees of freedom. Here, tunneling injection of single electrons into the upper Hubbard band of the Mott charge-density-wave material 1T-TaS2 reveals extraordinarily narrow electronic excitations which couple to amplitude mode phonons associated with the charge density wave's periodic lattice distortion. This gives a vivid microscopic view of the interplay between excitations of the Mott state and the lattice dynamics of its charge density wave precursor.