Failure of the Wiedemann-Franz law in mesoscopic conductors
نویسندگان
چکیده
We study the effect of mesoscopic fluctuations on the validity of the Wiedemannn-Franz WF law for quasi-one-dimensional metal wires and open quantum dots. At temperatures much less than the generalized Thouless energy, Ec, the WF law is satisfied for each specific sample, but as the temperature is raised through Ec, a sample-specific correction to the WF law of order 1/g appears g is the dimensionless conductance and then tends to zero again at kBT Ec. The mesoscopic violation of the Weidemann-Franz law is even more pronounced in a ring geometry for which the Lorenz number exhibits h /e flux-periodic Aharonov-Bohm oscillations.
منابع مشابه
Violation of the Wiedemann-Franz Law in Hydrodynamic Electron Liquids.
The Wiedemann-Franz law, connecting the electronic thermal conductivity to the electrical conductivity of a disordered metal, is generally found to be well satisfied even when electron-electron (e-e) interactions are strong. In ultraclean conductors in the hydrodynamic regime, however, large deviations from the standard form of the law are expected, due to the fact that e-e interactions affect ...
متن کاملd-density wave state in an externalmagnetic field
We present a study of the electrical and thermal conductivities of the d-density wave (DDW) state in an external magnetic field B in the low temperature regime and in the presence of impurities. We show that in the zero temperature limit, T → 0, the Wiedemann-Franz (WF) law remains intact. For finite T the WF law violation is possible and it is enhanced by the external field.
متن کاملThermo-Electric Properties of One-Dimensional Constrictions
This thesis describes low-temperature transport measurements in low-dimensional systems fabricated in high-mobility GaAs/AlGaAs heterostructures. These lowdimensional systems are formed by electrostatically constricting the electrons in the two-dimensional electron gas at the interface of the heterostructure, by applying a voltage to a pair of metallic gates known as a split-gate. At low temper...
متن کاملAnomalously low electronic thermal conductivity in metallic vanadium dioxide.
In electrically conductive solids, the Wiedemann-Franz law requires the electronic contribution to thermal conductivity to be proportional to electrical conductivity. Violations of the Wiedemann-Franz law are typically an indication of unconventional quasiparticle dynamics, such as inelastic scattering, or hydrodynamic collective motion of charge carriers, typically pronounced only at cryogenic...
متن کاملApparent violation of the Wiedemann-Franz law near a magnetic field tuned metal-antiferromagnetic quantum critical point.
The temperature dependences of the interlayer electrical and thermal resistivity in a layered metal are calculated for Fermi liquid quasiparticles which are scattered inelastically by two-dimensional antiferromagnetic spin fluctuations. Both resistivities have a linear temperature dependence over a broad temperature range. Extrapolations to zero temperature made from this linear-T range give va...
متن کامل