At low temperatures, EuTiO3 system has very large resistivities and exhibits colossal magnetoresistance. Based on a first principle calculation and the dynamical mean-field theory for small polaron we have calculated the transport properties of EuTiO3. It is found that due to electron-phonon interaction the conduction band may form a tiny subband which is close to the Fermi level. The tiny subband is responsible for the large resistivity. Besides, EuTiO3 is a weak antiferromagnetic material and its magnetization would slightly shift the subband via exchange interaction between conduction electrons and magnetic atoms. Since the subband is close to the Fermi level, a slight shift of its position gives colossal magnetoresistance.
@article{arxiv.1703.02238,
title = {Strong Electron-Phonon Interaction and Colossal Magnetoresistance in EuTiO$_3$},
author = {Ruofan Chen and Ji-Chang Ren and Km Rubi and R. Mahendiran and Jian-Sheng Wang},
journal= {arXiv preprint arXiv:1703.02238},
year = {2018}
}