Year: 2025
Type: article
Abstract: Low-energy excitations in correlated electron systems may show intricate behaviors and provide essential insights into the dynamics of quantum states and phase transitions. Here, we study a typical half-filled two-orbital Hubbard model featuring the so-called holon-doublon (HD) low-energy excitations in the orbital-selective Mott phase (OSMP), where the principal form of the low-energy excitations has been considered to be a HD bound state. We employ standard single-site dynamical mean-field theory (DMFT), using NORG as an improved impurity solver to calculate the spectral functions at zero temperature. We show that the HD bound state gives an incomplete or even wrong picture for the low-energy excitations. Instead, the excitations are composed of a Kondo-like state in the wide band and a doublon in the narrow band, termed as interband Kondo-like (IBK) bound states. Remarkably, we find that, as the bandwidths of the two bands approach each other, anomalous IBK bound-state excitations appear in the metallic wide band. Our study provides a new picture for the low-energy excitations in the OSMP.
Institution: Renmin University of China
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G6014283106, G8050988262
OpenAlex ID: W4409132320