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Research Highlight: Tempelaar

Microscopic theory of cavity-confined monolayer semiconductors: polariton-induced valley relaxation and the prospect of enhancing and controlling the valley pseudospin by chiral strong coupling

A detailed control of the quantum states of materials offers the prospect of revolutionizing information technology. A particularly interesting class of materials in this respect are transition-metal dichalcogenides (TMDs). TMDs are direct-bandgap, semiconducting atomic monolayers, where a combination of inversion-symmetry breaking and spin-orbit coupling yields two inequivalent corners of the hexagonal Brillouin zone, referred to as "valleys''. The distinct spin and optical selection rules of these valleys enables one to couple between circularly-polarized light and well-defined valley and spin quantum numbers of the material. Previous experimental studies have shown that embedding TMDs in an optical cavity consisting of two parallel reflectors holds potential to increase the valley and spin relaxation times, improving our ability to control and manipulate such quantum states. Professor Roel Tempelaar's group has performed a theoretical/numerical study of cavity-confined TMDs, and the hybrid light-matter states that emerge in such systems. Our results demonstrate that valley and spin relaxation depend strongly on the circularly-polarized properties of the cavity, and that control of these properties opens the way to further enhance the relaxation times. In addition, we show that cavity implementations exclusive to one particular circularly-polarized handedness further extends our abilities to control chiral light-matter excitations. This offers an additional domain onto which quantum information may be mapped. 

Salij & TempelaararXiv (2020)



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