2023/11/03 by Nadine Leisgang, Leisgang, Nadine, Dmitry Miserev +15 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #Strongly Correlated Electrons (cond-mat.str-el) #Surface and Thin Film Phenomena
paper · pdf · doi:10.48550/arxiv.2311.02164
openalex publication_date 2023/11/03 · openalex created_date 2023/11/08 · openalex updated_date 2026/07/30
Mobile electrons in the semiconductor monolayer-MoS2 form a ferromagnetic state at low temperature. The Fermi sea consists of two circles, one at the K-point, the other at the K-point, both with the same spin. Here, we present an optical experiment on gated MoS2 at low electron-density in which excitons are injected with known spin and valley quantum numbers. The resulting trions are identified using a model which accounts for the injection process, the formation of antisymmetrized trion states, electron-hole scattering from one valley to the other, and recombination. The results are consistent with a complete spin polarization. From the splittings between different trion states, we measure the exchange energy, Σ, the energy required to flip a single spin within the ferromagnetic state, as well as the intervalley Coulomb exchange energy, J. We determine Σ=11.2 meV and J=5 meV at n=1.5 × 1012 cm-2, and find that J depends strongly on the electron density, n.