Coherent response of spin-orbit split-off excitons in InP: Isolation of many-body effects through interference

Abstract

The spin-orbit split-off (SO) exciton is observed in a III-V semiconductor (InP) using spectrally resolved four-wave mixing (SR-FWM) with 1.515 eV, 35 fs pulses at 77 K. Interference between the coherent response of the SO exciton and that of electron-hole pairs in continuum states leads to frequency- and time-dependent signatures that can be directly attributed to excitation-induced dephasing (EID) of the SO exciton. Many-body effects can therefore be isolated from free induction decay contributions, in contrast to experiments that probe the fundamental exciton. Simulations employing the multiband Boltzmann-Bloch equations including EID effects corroborate our experimental results.