# Condensed Matter Physics Seminar

2 p.m., Thursday, December 6
Room 1201, Physics Building

## Boris Narozhny

### (Department of Physics, Brookhaven National Laboratory)

Abstract:  It is well known that electron-electron interaction in disordered systems leads to logarithmically divergent Altshuler-Aronov corrections to conductivity at low temperatures ($T\tau\ll 1$; $\tau$ is the elastic mean-free time). In this talk I discuss the fate of such corrections at intermediate temperatures $T\tau\ge 1$. In that (ballistic) regime the temperature dependence of conductivity is still governed by the same physical processes as the Altshuler-Aronov correction - scattering by Friedel oscillations. However, in that regime the correction is linear in temperature; the value and even the {\em sign} of the slope depends on the strength of electron-electron interaction. The slope is directly related to the renormalization of the spin susceptibility and grows as the system approaches the ferromagnetic Stoner instability. Also, I discuss the effect of electron-electron interaction on the temperature dependence of the Hall coefficient. At small temperature $T\tau \ll \hbar$ the known relation between the logarithmic temperature dependences of the Hall coefficient and of the longitudinal conductivity holds. At higher temperatures, this relation is violated quite rapidly; the correction to the Hall coefficient becomes $\propto 1/T$ unlike the longitudinal conductivity which is linear in $T$.
Host:  Sankar Das Sarma