Anomalous Behavior of the Dephasing Time in Open Diffusive Cavities

概要

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The dcphasing due to electron-electron Coulomb interactions is studied for open mesoscopic cavitiesin the diffusive regime where l/λ_p ≫ 1( l : elastic mean free path, λ_p : Fermi wavelength). We consider a square cavity with area L x L, which is connected to reservoirs through a pair of thin leads of width W. Itis assumed that L ≫ W ≫ L The system is characterized by the lowest eigenvalue Γ_0 of a diffusion equation. We find that the temperature dependence of the dephasing time t_φ changes whether temperature T is higher or lower than T_<cross> ≡ Γ_0/k_B. It is shown that t_φ behaves as t^^<1->_φ∝T when T ≫ T_<cross>. If T is decreased below T_<cross>, the T-dependence of t_φ crosses over to t^^<1->_φ∝T^2. It is also shown that in the high-temperature regime of T ≫ T_<cross>, the dephasing time is greatly reduced incomparison with that in an ordinary two-dimensional system.
社団法人日本物理学会の論文
2003-02-15