1999/01/27 by Pavol Farkašovský, P. Farkasovsky, Farkasovsky, P.
Physics and Astronomy · #Advanced Chemical Physics Studies #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #Theoretical and Computational Physics #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.cond-mat/9901312
12 pages, 6 figures
arxiv created 1999/01/27 · openalex publication_date 1999/01/27 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The ground-state phase diagram of the spin-one-half Falicov-Kimball model (FKM) is studied in the one dimension using small-cluster exact-diagonalization calculations. The resultant exact solutions are used to examine possibilities for valence and metal-insulator transitions in this model. A number of remarkable results are found. (i) The phase separation in the spin-one-half FKM takes place for a wide range of f-electron concentrations nf and d-f interactions G, including G large. (ii) In the strong coupling limit (G>4) the model exhibits a pressure induced discontinuous insulator-metal transition from an integer-valence state (nf=1) into another integer-valence state (nf=0). (iii) For intermediate values of G (G∼ 2.5) the FKM undergoes a few discontinuous intermediate-valence transitions. There are several discontinuous insulator-insulator transitions from nf=1 to nf=1/2 and a discontinuous insulator-metal transition from nf = 1/2 to nf=0. (iv) In the weak coupling limit (G<2) the model undergoes a few consecutive discontinuous and continuous intermediate-valence transitions as well as a discontinuous metal-insulator transition.