Acoustically-modulated exciton dynamics in twisted van der Waals heterostructures

• Grant number: 21/06803-4
• Support type: Research Grants - Young Investigators Grants - Phase 2
• Duration: February 01, 2022 - January 31, 2027
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal researcher: Odilon Divino Damasceno Couto Júnior
• Grantee: Odilon Divino Damasceno Couto Júnior
• Home Institution: Instituto de Física Gleb Wataghin (IFGW). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 12/11382-9 - Optical modulation of semiconductor nanostructures using surface acoustic waves, AP.JP
• Associated scholarship(s): 22/03323-4 - Generation and characterization of standing wave patterns in surface acoustic wave delay lines, BP.IC; 22/01839-3 - Growth and optical characterization of transition metal dichalcogenides epitaxial layers, BP.MS

Abstract

Van der Waals (vdW) heterostructures formed by artificially stacking transition metal dichalcogenide monolayers are one of the most attractive research playgrounds in solid-state physics nowadays. vdW heterostructures constructed with semiconductor monolayers find their niche in optoelectronics, valleytronics, and (the more recent) twistronics fundamental and applied research. Their symmetry-governed unique Coulomb interaction, correlations, and spin-orbit coupling provide a magnificent platform for tailoring many-body state interactions and, in particular, exciting non-conventional excitonic states.In this project, we will address the surface acoustic wave (SAW) modulation of light-matter interaction in different nanostructures with emphasis in the manipulation of excitonic states and carrier transport in twisted vdW heterostructures. We will investigate how the high-frequency SAW piezoelectric potential and mechanical deformation interact with different quantum states (like intralayer, interlayer, and moiré excitons) in vdW heterostructures which have their twist angle and dielectric environment precisely tailored by deterministic placement. We will employ SAWs to tune their symmetry-governed properties in order to manipulate the excitonic interaction strength, modulate recombination energies, induce the formation/annihilation of excitonic states, change valley scattering mechanisms, and (eventually) position-dependent optical selection rules. Carrier transport and remote injection in high mobility lateral vdW heterostructures will also be investigated. To achieve our goals, we will set up new experiments like SAW-modulated second-harmonic generation and stroboscopic light detection. The success of our proposal will allow us to shed light in the fundamental properties of excitonic states in vdW heterostructures as well as to evaluate their application in future quantum information devices which explore their twist and spin-valley properties. (AU)