Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tuning of the CDW in the Halogen-Bridged Transition-Metal Linear-Chain
  Compounds   Local-density-approximation calculations are used to show that the
metal-metal distance along the chains controls the charge-density wave (CDW) in
halogen-bridged transition-metal linear-chain (MX) compounds. The strength of
the CDW can be understood in terms of a two band Su-Schrieffer-Heeger model if
a hard-core ion-ion repulsion potential is also added. We predict a
second-order phase transition from an insulating to a semi-metallic ground
state and explain trends in dimerization, bond-length ratios, band gaps, and
Raman breathing modes in terms of the metal-metal distance. Three "ps" figures
are included at the end of the file.

24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess