抄録
The dephasing due to electron–electron Coulomb interactions is studied for open mesoscopic cavities in the diffusive regime where l⁄λF>>1 (l: elastic mean free path, λF: Fermi wavelength). We consider a square cavity with area L×L, which is connected to reservoirs through a pair of thin leads of width W. It is assumed that L>>W>>l. The system is characterized by the lowest eigenvalue Γ0 of a diffusion equation. We find that the temperature dependence of the dephasing time τφ changes whether temperature T is higher or lower than Tcross≡Γ0⁄kB. It is shown that τφ behaves as τφ−1∝T when T>>Tcross. If T is decreased below Tcross, the T-dependence of τφ crosses over to τφ−1∝T2. It is also shown that in the high-temperature regime of T>>Tcross, the dephasing time is greatly reduced in comparison with that in an ordinary two-dimensional system.
