The electron dephasing processes in two-dimensional homogeneous and inhomogeneous indium tin oxide thin films have been investigated in a wide temperature range 0.3–90 K. We found that the small-energy-transfer electron-electron ($e$-$e$) scattering process dominated the dephasing from a few kelvins to several tens of kelvins. At higher temperatures, a crossover to the large-energy-transfer $e$-$e$ scattering process was observed. Below about 1 to 2 K, the dephasing time ${\tau }_{\varphi }$ revealed a very weak temperature dependence, which intriguingly scaled approximately with the inverse of the electron diffusion constant $D$, i.e., ${\tau }_{\varphi }(T\approx 0.3\mathrm{K})\propto 1/D$. Theoretical implications of our results are discussed. The reason why the electron-phonon relaxation rate is negligibly weak in this low-carrier-concentration material is presented.

• Received 3 October 2011

DOI:https://doi.org/10.1103/PhysRevB.85.104204