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Title: Giant Valley-Zeeman Splitting from Spin-Singlet and Spin-Triplet Interlayer Excitons in WSe2/MoSe2 Heterostructure

Journal Article · · Nano Letters

Transition metal dichalcogenides (TMDCs) heterostructure with a type II alignment hosts unique interlayer excitons with the possibility of spin-triplet and spin-singlet states. However, the associated spectroscopy signatures remain elusive, strongly hindering the understanding of the Moiré potential modulation of the interlayer exciton. In this work, we unambiguously identify the spin-singlet and spin-triplet interlayer excitons in the WSe2/MoSe2 heterobilayer with a 60° twist angle through the gate- and magnetic field-dependent photoluminescence spectroscopy. Both the singlet and triplet interlayer excitons show giant valley-Zeeman splitting between the K and K" valleys, a result of the large Landé g-factor of the singlet interlayer exciton and triplet interlayer exciton, which are experimentally determined to be ~10.7 and ~15.2, respectively, which is in good agreement with theoretical expectation. The photoluminescence (PL) from the singlet and triplet interlayer excitons show opposite helicities, determined by the atomic registry. Helicity-resolved photoluminescence excitation (PLE) spectroscopy study shows that both singlet and triplet interlayer excitons are highly valley-polarized at the resonant excitation with the valley polarization of the singlet interlayer exciton approaching unity at ~20 K. The highly valley-polarized singlet and triplet interlayer excitons with giant valley-Zeeman splitting inspire future applications in spintronics and valleytronics.

Research Organization:
Florida State Univ., Tallahassee, FL (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
FG02-07ER46451
OSTI ID:
1800506
Journal Information:
Nano Letters, Vol. 20, Issue 1; ISSN 1530-6984
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English

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