Compositional dependence of the exciton reduced mass in GaAs1-xBix (x=0-10%)

摘要: We report the compositional dependence of exciton reduced mass, ${\ensuremath{\mu}}_{\text{exc}}$, ${\text{GaAs}}_{1\ensuremath{-}x}{\text{Bi}}_{x}$ in a very large Bi concentration range $(x=0\text{--}10.6\mathrm{%})$. Photoluminescence under high magnetic fields ($B$ up to 30 T) shows that ${\ensuremath{\mu}}_{\text{exc}}$ increases rapidly until $x\ensuremath{\sim}1.5\mathrm{%}$ and then oscillates around $\ensuremath{\sim}0.08\text{ }{m}_{0}$, ${m}_{0}$ being electron mass vacuum, about $x=6\mathrm{%}$. Surprisingly, for $xg8\mathrm{%}$ decreases below GaAs value, agreement with expectations $k\ensuremath{\cdot}p$ model. Such behavior reveals existence different intervals, where continuum states valence conduction band hybridize Bi-related levels at extents, thus conferring edges localized or bandlike character $xl6\mathrm{%}$ $xg8\mathrm{%}$, respectively.