A research team led by Prof. Ning Cunzheng, dean of College of Integrated Circuits and Optoelectronic Chips at Shenzhen Technology University (SZTU), has achieved a landmark breakthrough in semiconductor physics, experimentally confirming the existence of a genuine four-particle entity, named the quadruplon. A paper titled “The quadruplon in a monolayer semiconductor” is published in the prestigious journal eLight. This discovery challenges classical semiconductor theories and opens unprecedented avenues for the development of quantum technology.

Basics of experiment and key observations [Photo/https://doi.org/10.1186/s43593-025-00081-1]

A cluster expansion picture of a four-body system. [Photo/https://doi.org/10.1186/s43593-025-00081-1]

In this paper, the researchers present for the first time the experimental evidence for the existence of a four-body entity in condensed matter, the quadruplon, involving two electrons and two holes in a monolayer of Molybdenum Ditelluride (ML-MoTe2). Using the helicity-resolved pump–probe technique, they observed a series of spectral features in the transient reflectance in a wide range of probe photon energies in gate-controlled ML-MoTe2 samples. Up to six spectral peaks were revealed, which defies existing quasiparticle models and cannot be attributed to defects or phonon-related processes. By using the corresponding cluster expansion technique, such theory–experiment comparison shows that the quadruplon is necessary and sufficient in producing all the experimental spectral features, thus providing experimentally spectroscopic signatures of the existence of the quadruplons. The results could impact the understanding of the structure of materials in a wide range of physical systems and potentially lead to new photonic applications based on quadruplons.

Drafted by Daisy（姚琦）/ International Cooperation and Exchanges Department

Revised by Brian（郑斌）/ International Cooperation and Exchanges Department

Edited by Brian（郑斌）/ International Cooperation and Exchanges Department