Metallization and metallicity: universal conductivity limits

Ganguly, P. (2004) Metallization and metallicity: universal conductivity limits Current Opinion in Solid State and Materials Science, 8 (6). pp. 385-395. ISSN 1359-0286

Full text not available from this repository.

Official URL:

Related URL:


The Mott-Ioffe-Regel minimum metallic conductivity based on a minimum mean free path of inter-atomic spacing has been used as a robust criterion for signalling Fermi liquid behaviour. Instead we examine the conductivity of a system in universal terms of the excitation energy, Eexc, of a charge carrier bound to its hole. The expression for conductivity depends simply on probability of charge transfer expressed as Eexc/h. The minimum conductivity for Fermi liquid state is obtained as σ min (FL) = CEmax exc/h = 11, 360 S cm-1 (C = 1; Emax exc = 6.8 eV is the maximum excitonic binding energy for a mobile exciton). From simple considerations in the t-J model of the Larmor precession time, τintL, due to an internal exchange magnetic field and the residence time, τW, for a charge carrier with energy EW, we express condition for Fermi liquid (τintLW > 1) and non-Fermi liquid behaviour ((τintLW<1)). For such NFL liquids, we find that one requires CNFL = (1/π2π2/3) ~1/21.2 to account for the reduced probability of charge transfer with conservation of spin in NFL systems. The maximum value of the conductivity, σ±, at which the temperature coefficient of resistance (TCR) changes sign at an insulator metal transition is given by σ± max(IM) = CNFL σmin(FL) ≈ 536 S cm-1. This value is close to that observed in several systems. We discuss these universal values of the conductivity in the context of the Herzfeld criterion, Mooij criterion, exciton transfer rates, chemical reaction rate theory, universal sheet resistance at insulator-superconductor transition, as well as the changes in resistivity during the metallization of molecular hydrogen, oxygen and iodine.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Metallization; Metallicity; Herzfeld Criterion; Minimum Metallic Conductivity; Mooij Limit; Fermi Liquid; Non-fermi Liquid; Critical Sheet Resistance; Metallic Hydrogen; Larmor Times; Mott Hubbard Limit
ID Code:13837
Deposited On:12 Nov 2010 14:38
Last Modified:31 May 2011 09:33

Repository Staff Only: item control page