Band structure, g -factor, and spin relaxation in n -type InAsP alloys

We present experimental and theoretical studies of the magneto-optical properties of $n$-type ${\mathrm{InAs}}_{x}{\mathrm{P}}_{1\ensuremath{-}x}$ films in ultrahigh magnetic fields at room temperature. We compare Landau level and band structure calculations with observed cyclotron resonance (CR) measurements and extract effective $g$-factors and CR masses for two different alloy concentrations, $x=0.07$ and $x=0.34$. In addition, we employ time-resolved magneto-optical Kerr measurements on these ternary alloys to explore the spin relaxation time. These alloys have immense prospects for quantum communication devices and $g$-factor engineering, and our study provides insights into this underexplored narrow-gap system.