Photoemission signatures of photoinduced carriers and excitons in one-dimensional Mott insulators
Phys. Rev. B 114, 065119 – Published 14 July, 2026
DOI: https://doi.org/10.1103/bfhz-lhjk
Abstract
We theoretically study photoemission spectra of photodoped one-dimensional Mott insulators that can host an excitonic bound state of a doublon and a holon known as a Mott–Hubbard exciton. We show that their spectral characteristics differ qualitatively from those of photodoped semiconductors. In conventional semiconductors, photoemission spectra are well understood; free charge carriers generate spectral weight near the bottom of the conduction band, while the formation of excitons leads to replica features of the valence band appearing inside the band gap. In one-dimensional Mott insulators, on the other hand, strong correlations give rise to fractionalized elementary excitations—spinons, holons, and doublons—which fundamentally modify the photoemission response. We find that when photodoped carriers, i.e., doublons and holons, remain unbound, the photoemission spectrum directly reflects the dispersion of spinons, i.e., magnetic elementary excitations. In contrast, when a doublon and a holon form a Mott–Hubbard exciton, replica structures of the lower Hubbard band emerge within the Mott gap, carrying contributions from both spinon and holon excitations. Importantly, the distribution of the in-gap signal depends sensitively on the degree of doublon–holon binding. The origin of these spectral features is clarified through a combination of exact diagonalization and the slave-particle approach. These results indicate that photoemission from photoinduced carriers and excitons in strongly correlated electron systems can provide information on magnetic properties and carrier binding properties.
