paper

Lieb-Schultz-Mattis constraints for the insulating phases of the one-dimensional SU() Kondo lattice model

arXiv:2404.11030 · doi:10.1103/PhysRevB.110.075104

Abstract

The nature of the insulating phases of the SU()-generalization of the one-dimensional Kondo lattice model is investigated by means of non-perturbative approaches. By extending the Lieb-Schultz-Mattis (LSM) argument to multi-component fermion systems with translation and global SU() symmetries, we derive two indices which depend on the filling and the ``SU()-spin'' (representation) of the local moments. These indices strongly constrain possible insulating phases; for instance, when the local moments transform in the -dimensional (defining) representation of SU(), a featureless Kondo insulator is possible only at filling . To obtain further insight into the insulating phases suggested by the LSM argument, we derive low-energy effective theories by adding an antiferromagnetic Heisenberg exchange interaction among the local moments [the SU() Kondo-Heisenberg model]. A conjectured global phase diagram of the SU() Kondo lattice model as a function of the filling and the Kondo coupling is then obtained by a combination of different analytical approaches.

29 pages, 6 figures

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