Acoustic modulation of van der Waals heterostructures: exciton dynamics and single photon emission

• Grant number: 24/23228-1
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: May 01, 2025
• End date: January 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Odilon Divino Damasceno Couto Júnior
• Grantee: Pedro Winckler Matrone
• Supervisor: Alberto Hernandez Minguez
• Host Institution: Instituto de Física Gleb Wataghin (IFGW). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Paul-Drude-Institut für Festkörperelektronik (PDI), Germany
• Associated to the scholarship: 23/00191-2 - Acoustic carrier and spin transport in transition metal dichalcogenide heterostructures, BP.DD

Abstract

In this visiting research scholarship (BEPE) project, we will investigate the dynamics of excitonic complexes in different van der Waals heterostructures when modulated by surface acoustic waves (SAWs). In hBN/1L-MoSe2/hBN, we intend to understand an apparent population transfer between neutral excitons and trions which we have observed. This effect can be tuned and reversed by the SAW piezoelectric field, but there are still remaining questions we need to answer in order to fully understand it. In hBN/2L-MoSe2/hBN homobilayer systems with different twist angles, we will describe the interaction of the localized moiré excitons and the SAW by probing the efficiency of the wave in tuning the energy emission and intensity of these excitonic complexes. We hope that the ability of the SAW in modifying the optical emission in these systems can help us to contribute to a broader understanding of the nature of these symmetry-dependent narrow excitonic lines. We will also investigate single-photon emission modulated by SAWs in 1L-WSe2 exfoliated in nanopillar arrays and fabricate focusing transducer devices to generate enhanced acoustic fields in TMD-based structures. To achieve these goals, we will employ different acoustic modulated optical spectroscopy techniques including interferometric, CW and time-resolved photoluminescence, and second order correlation measurements. This is a joint effort between our group in Campinas and the group of Dr. Alberto Hernández-Mínguez at the Paul Drude Institute in Berlin. It will also count with the contribution from the group of Prof. Stephan Reitzenstein at the Technical University of Berlin.