Dielectric measurement to probe electron ordering and electron-spin interaction

Here we found that dielectric measurement can be a sensitive probe to detect the behavior of electrons and electron-spin interaction in a strongly electron-correlated system. The CuO single crystal samples with and without excess holes were investigated by dielectric measurements in combination with magnetic susceptibility measurement. Only for the semiconducting single crystal with holes was dynamic dielectric relaxation with prominent frequency dispersion and large dielectric constants observed, suggesting localization of holes in the lattice. Coupling of hole and spin was directly observed by dielectric anomalies at the magnetic phase transitions. A pseudoferroelectric-like characteristic in the E–P plot was also observed. This study verifies that the holes are strongly coupled both to the vibrational and magnetic degrees of freedom in CuO. It also suggests the possibility of using dielectric measurement as a tool to investigate the coupling of electron and spin in strong correlated systems.