Influence of many-body effects on hole quasiparticle dynamics in a WS2 monolayer

Monolayer (ML) transition metal dichalcogenides (TMDCs) emerged as ideal materials to combine spin and momentum of charge carriers for spintronics and valleytronics applications. Despite its relevance for TMDC-based technology, the impact of the various many-body-like interactions of charge carriers with defects, phonons, and other system's quasiparticles on the charge dynamics and transport properties remains experimentally elusive, being commonly overshadowed by the strong ML interactions with other materials (such as substrate and contacts) introduced in standard experimental approaches. Here, a method combining interface engineering and angle-resolved photoemission spectroscopy (ARPES) enables a direct investigation of the impact of many-body effects on the hole quasiparticle dynamics of WS2 ML on graphite and extraction of relevant transport parameters. In particular, at the valence band edge, a clear ARPES line-shape asymmetry is observed, mainly reflecting the hole interaction with intralayer electrons and defects while a negligible hole-phonon coupling is found. Using the valley hole quasiparticle lifetime and effective mass extracted from ARPES data at different temperatures, we estimated a hole mobility of similar to 300 cm(2) V-1 s(-1), comparable to some of the highest values reported by transport measurements.

Automated summary

The study utilizes interface engineering and ARPES technique to investigate the hole quasiparticle dynamics of TMDC material WS2 monolayer on graphite, and extracts relevant transport parameters. It observes the interaction between holes and electrons/defects, and quantitatively estimates their impact.