Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase separation and metal-insulator transitions in the spin-one-half
  Falicov-Kimball model   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 $n_f$ 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 ($n_f=1$) into another integer-valence
state ($n_f=0$). (iii) For intermediate values of $G$ ($G\sim 2.5$) the FKM
undergoes a few discontinuous intermediate-valence transitions. There are
several discontinuous insulator-insulator transitions from $n_f=1$ to $n_f=1/2$
and a discontinuous insulator-metal transition from $n_f = 1/2$ to $n_f=0$.
(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.

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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
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The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
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The categories of this paper are: eess
29
The categories of this paper are: funct-an
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: acc-phys