ELECTRON DEPHASING DUE TO COULOMB INTERACTION

The electron-electron scattering time tau-ee for a hot electron with excess energy DELTA above the Fermi surface of a two-dimensional (2D) electron gas is calculated as a function of temperature, carrier density, and excess energy DELTA for a typical heterostructure, tau-ee increases with decreasing temperature and saturates for temperatures below kT < DELTA. The electron-electron scattering length l(ee) limits the size of electron quantum interference devices. We show that electron-electron scattering lengths l(ee) around 1 mm should be possible at temperatures T below 1 K and electron energies DELTA below 0.1 meV.