Microscopic Mechanism of Stripe Pairing Phase Formation

Abstract

Stripe phase formation in manganite compounds with the colossal magnetoresistance is discussed on the basis of the cooperative Jahn-Teller effect theory. It is shown that the stripes are the result of a peculiar structural phase transition. The microscopic mechanism of this structural ordering is considered and it is found that the interference of two symmetry types of distortion ordering takes place, that of totally symmetrical and Jahn-Teller distortions. The quadratic electron-phonon interaction after two-mode canonical transformation leads to a three center interaction responsible for the stability of a combination of local distortions around the nearest neighbor Mn3+-Mn4+-Mn3+ ions as a structural unit of a stripe. The described combination of the local distortions is in agreement with the experimentally observed electron diffraction pattern.