Condensed Matter Physics Seminar
2 p.m., Thursday, December 6
Room 1201, Physics Building
Interaction corrections to transport coefficients in two-dimensional
electron gas at intermediate temperatures
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 $T$.
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Host: Sankar Das Sarma
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