Phase separation tendencies in manganites as a possible explanation of the CMR effect

Abstract

This paper is a brief review of the present status of the computational studies of models for manganites that recently reported the existence of phase separation at low-temperatures (S. Yunoki et al., Phys. Rev. Lett. 80, 845 (1998); 81, 5612 (1998) and references therein). Results for both the one-orbital and two-orbital models, the latter with Jahn–Teller phonons, are discussed. The spin-canted phase widely believed until recently to exist at low hole-density is not stable. The tendencies to charge clustering suggest that local mean-field approaches may not be suitable for the study of models for manganites, especially at finite temperatures where the phase separation tendencies will be dynamic rather than static. A large list of experimental results are compatible with the existence of charge-inhomogeneities in the manganites, which may be an important ingredient for the explanation of the CMR effect in these compounds.