Year: 2008
Type: article
Abstract: We study the Kondo-Heisenberg model using a fermionic representation for the localized spins. The mean-field phase diagram exhibits a zero-temperature quantum critical point separating a spin liquid phase where the $f$-conduction hybridization vanishes and a Kondo phase where it does not. Two solutions can be stabilized in the Kondo phase, namely, a uniform hybridization when the band masses of the conduction electrons and the $f$ spinons have the same sign and a modulated one when they have opposite sign. For the uniform case, we show that above a very small Fermi-liquid temperature scale, the critical fluctuations associated with the vanishing hybridization have dynamical exponent $z=3$, giving rise to a specific-heat coefficient that diverges logarithmically in temperature, as well as a conduction-electron inverse lifetime that has a $T\text{ }\text{log}\text{ }T$ behavior. Because the $f$ spinons do not carry current, but act as an effective bath for the relaxation of the current carried by the conduction electrons, the latter result also gives rise to a $T\text{ }\text{log}\text{ }T$ behavior in the resistivity. This behavior is consistent with observations in a number of heavy fermion metals.
Source: Physical Review B
Authors: I. Paul, C. Pépin, M. R. Norman
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1975009243