Shubnikov-de Haas measurement of electron effective mass in GaAs1−xBix

Magnetic field and temperature dependent resistivity measurements on n-type GaAs1-xBix epitaxially grown films show clear Shubnikov de Haas oscillations in the range 0 ≤ x ≤ 0.0088. An overall decrease in the electron effective mass is observed for this range of compositions. Accounting for the known giant bandgap bowing and giant spin orbit bowing, the measured changes in the effective mass are in qualitative agreement with perturbation theory applied to these energy band changes, confirming that bismuth mainly perturbs the valence band. The stronger compositional dependence of the measured mass is attributed to effects from the bismuth isolated state.