NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Neutral and Charged Inter-Valley Biexcitons in Monolayer MoSe2
Published
Author(s)
Lixiang Xu, Judith Specht, Philip Nagler, Kha Tran, Akshay Singh, Chandriker K. Dass, Andreas Knorr, Xiaoqin Li, Galan Moody
Abstract
In atomically thin transition metal dichalcogenides (TMDs), reduced dielectric screening of the Coulomb interaction leads to strongly correlated many-body states, including excitons and trions, that dominate the optical properties. Higher-order states, such as bound biexcitons, are possible but are difficult to identify unambiguously using linear optical spectroscopy methods alone. Here, we implement polarization-resolved two-dimensional coherent spectroscopy to unravel the complex optical response of monolayer MoSe2 and identify multiple higher-order correlated states. Decisive signatures of neutral and charged inter-valley biexcitons appear in cross-polarized two- dimensional spectra as distinct resonances with respective 20 meV and 5 meV binding energies—similar to recent calculations using variational and Monte Carlo methods. A theoretical model taking into account the valley-dependent optical selection rules reveals the specific quantum pathways that give rise to these states. Inter-valley biexcitons identified here—comprised of neutral and charged excitons from different valleys—offer new opportunities for creating exotic exciton-polariton condensates and for developing ultrathin biexciton lasers and polarization-entangled photon sources.
Xu, L.
, Specht, J.
, Nagler, P.
, Tran, K.
, Singh, A.
, Dass, C.
, Knorr, A.
, Li, X.
and Moody, G.
(2017),
Neutral and Charged Inter-Valley Biexcitons in Monolayer MoSe2, Nature Communications, [online], https://doi.org/10.1038/ncomms15552, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921758
(Accessed October 13, 2025)