Two-band model for NbSe/sub 3/ (Ohmic regime)

Journal Article · Wed Nov 15 00:00:00 EST 1978 · Phys. Rev., B: Solid State; (United States)

DOI:https://doi.org/10.1103/PhysRevB.18.5272· OSTI ID:6427676

Ong, N P

The charge-density-wave (CDW) linear-chain metal NbSe/sub 3/ shows :e striking non-Ohmic behavior when the applied electric field exceeds approx. 0.1 V/cm. Hall effect, transverse magnetoresistance, conductivity anisotropy, and Shubnikov--de Haas measurements using sufficiently low current densities to avoid Ohmic breakdown have been published. We propose a simple two-band model to account for the temperature dependence of these quantities as well as the (magnetic) field dependence of the Hall constant in the Ohmic regime below 58 K. The model has six unknowns (carrier concentrations and mobilities) that are fixed by six experimental numbers at each temperature T. The solution shows that all the mobilities obey a power-law behavior versus T, whereas the carrier concentrations are both T independent up to 40 K. Above 40 K the hole population rises sharply, analogous to the theoretical predictions for an excitonic insulator. This implies that the CDW gap occurs on the hole surface. Using the parameters of the model, we have recomputed the resistivities, Hall constant, and magnetoresistance, and they have been shown to agree with all the available experimental data. Thus the conventional single-particle picture with the additional hypothesis of a BCS-type gap on the hole surface is adequate for understanding the transport properties of NbSe/sub 3/ in the zero-frequency-Ohmic regime. We also interpret the SdH data in terms of the two-band model.

• Research Organization: Department of Physics, University of Southern California, Los Angeles, California 90007
• OSTI ID: 6427676
• Journal Information: Phys. Rev., B: Solid State; (United States), Vol. 18:10
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
NIOBIUM SELENIDES
ELECTRONIC STRUCTURE
MAGNETORESISTANCE
SHUBNIKOV-DE HAAS EFFECT
ANISOTROPY
BAND THEORY
CHARGE DENSITY
ELECTRIC CONDUCTIVITY
HALL EFFECT
LOW TEMPERATURE
TEMPERATURE DEPENDENCE
VERY LOW TEMPERATURE
CHALCOGENIDES
ELECTRICAL PROPERTIES
NIOBIUM COMPOUNDS
PHYSICAL PROPERTIES
SELENIDES
SELENIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360104* - Metals & Alloys- Physical Properties