Electrical Control of Orbital and Vibrational Interlayer Coupling in Bi- and Trilayer 2H−mos2

Manipulating electronic inter layer coupling in layered van der Waals (vdW) materials is essential for designing opto-electronic devices. Here, we control vibrational and electronic inter layer coupling in bi- and trilayer 2H-MoS 2 using large external electric fields in a micro-capacitor device. The electric field lifts Raman selection rules and activates phonon modes in excellent agreement with ab-initio calculations. Through polarization resolved photoluminescence spectroscopy in the same device, we observe a strongly tunable valley dichroism with maximum circular polarization degree of ∼ 60% in bilayer and ∼ 35% in trilayer MoS 2 that are fully consistent with a rate equation model which includes input from electronic band structure calculations. We identify the highly delocalized electron wave function between the layers close to the high symmetry Q points as the origin of the tunable circular dichroism. Our results demonstrate the possibility of electric field tunable inter layer coupling for controlling emergent spin-valley physics and hybridization driven effects in vdW materials and their heterostructures