Fundamental ideas on metal-dielectric transitions in 3d-metal compounds
S.G. Ovchinnikova aKirensky Institute of Physics, Federal Research Center Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences, Academgorodok 50, str. 38, Krasnoyarsk, 660036, Russian Federation
The fundamental mechanisms of a metal-dielectric transition are examined. The multiband theory of the metal-dielectric transition is reviewed, as based on realistic models of the band structure of a set of oxides and sulfides of the 3d-metals in which the transition is accompanied by structural and magnetic phase transitions. In the multiband case new phases arise that were absent in the simplest single-band theories, yet at the same time are known experimentally. The metal-dielectric transition is studied in the Shubin--Vonsovskii model. It is shown that allowance for screening of the long-range Coulomb interaction leads to a first-order transition. We describe the concept of the metallic order parameter, which is proportional near the transition point to the density of states at the Fermi level. The theory enables one to explain qualitatively many experimental data, mainly thermodynamic, on the oxides of vanadium and titanium and the sulfides of 3d-metals having a metal-dielectric transition. The pathways are discussed of further development of the theory for fuller description of all physical properties of the materials being studied. Cases are analyzed in which localized magnetic moments exist and are manifested alongside the band states.
PT Journal Article
TI Fundamental ideas on metal-dielectric transitions in 3d-metal compounds
AU Zaitsev R O
FAU Zaitsev RO
AU Kuz’min E V
FAU Kuz’min EV
AU Ovchinnikov S G
FAU Ovchinnikov SG
DP 10 Apr, 1986
TA Phys. Usp.
SO Phys. Usp. 1986 Apr 10;29(4):322-342