Electronic Structure, Optical and Dielectric Spectroscopy Study of TbMnO3

TL;DR

This study investigates the electronic, optical, and dielectric properties of TbMnO3 single crystals, revealing insights into its band structure, optical transitions, and dielectric behavior near ferroelectric transition, using spectral ellipsometry and other spectroscopic methods.

Contribution

It provides the first spectral ellipsometry and photoluminescence data on TbMnO3, analyzing its dielectric response and phase transition behavior with theoretical modeling.

Findings

Dielectric permittivity peak decreases with frequency

Optical transitions characterized in the electronic band structure

Dielectric behavior explained by Landau-Khalatnikov theory

Abstract

Spectral ellipsometry studies of the optical functions, first observation of photoluminescence and low frequency dielectric permittivity investigations were performed in ferroelectric - multiferroic TbMnO3 single crystals. The main attention was paid to electronic band structure, nature of the main optical transitions and unusual behavior of the dielectric permittivity in the region of the sharp narrow temperature maximum, associated with ferroelectric phase transition. It was found that magnitude of the permittivity maximum decreases strongly with frequency, whereas position of maximum is frequency independent. Observed features of polarization response can be described satisfactorily in the frame of on the basis of the Landau-Khalatnikov theory for critical relaxation polarization