Large g factor in bilayer WS${}_2$ flakes

Abstract

The valley of transition metal dichalcogenides provides an additional platform to manipulate spin due to its unique selection rule. Normally, intralayer optical transitions in magnetic field show a Zeeman splitting with g factor of about $-4$. Here we report remarkable valley Zeeman effect exhibited by splitting of excitonic emission in a bilayer WS${}_2$, with a value of g factor as large as $-16.5$. The observed large g factor results from the interlayer recombination, as the conduction band and valence band are modified in opposite directions by magnetic field in different layers. The interlayer recombination is due to the defect induced inversion symmetry breaking, which is theoretically not accessible in ideal bilayer WS${}_2$ with inversion symmetry. Large g factor of interlayer emission offers potential benefits for future optical spin control and detection.

12 pages, 4 figures

References in corpus (5)

• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Magneto-optics in transition metal diselenide monolayers
• Excitonic valley effects in monolayer WS${}_2$ under high magnetic fields
• Longitudinal wave function control in single quantum dots with an applied magnetic field
• Magneto photoluminescence measurements of tungsten disulphide monolayers