News & Events

Quantum Materials and Devices Seminars

Electrical control of excitons in two-dimensional semiconductors

Nadine Leisgang (Harvard)

Wednesday, Feb 1, 2023
1:30 pm to 2:30 pm | Remote option

Zoom registration


The pursuit of scalable quantum technologies has led to an increasing demand for better control of quantum properties of materials. An exciton, a bound electron-hole pair, constitutes an atomic-like solid-state system which is optically accessible. In two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs), electron-hole pairs have particularly large binding energies, such that the excitons are stable even at room temperature. However, as the excitons are charge neutral, traditional depletion traps as employed for 2D electron gases will only provide weak confinement.

Here, we focus on TMD bilayer systems. We realize optical and electrical generation of interlayer excitons, where the bound electrons and holes reside in different layers. As a result of this separation the interlayer excitons are long-lived and have a large permanent dipole moment. Modulating the out-of-plane dipole through the distance of the electron and holes and through an applied electric field, the interlayer excitons can be controlled on a quantum level. The deterministic creation and control over interlayer exciton systems will open up new avenues for quantum applications.

N. Leisgang acknowledges support from the Swiss National Science Foundation (SNSF) (Grant No. P500PT_206917)


Emily Haderer