Determination of the Electron Masses in Stannic Oxide by Submillimeter Cyclotron Resonance

Submillimeter measurements of the effective masses yield values of ${m}_{\ensuremath{\perp}}^{*}=0.299{m}_{0}$ and ${m}_{\ensuremath{\parallel}}^{*}=0.234{m}_{0}$ for the electron. The density-of-states effective mass is $0.275{m}_{0}$. These direct measurements resolve the long-standing conflict among variety of reports which have ranged from 0.1 to $0.4{m}_{0}$.