Exchange energy of the ferromagnetic electronic ground-state in a monolayer semiconductor
| Autor: | Leisgang, Nadine, Miserev, Dmitry, Mattiat, Hinrich, Schneider, Lukas, Sponfeldner, Lukas, Watanabe, Kenji, Taniguchi, Takashi, Poggio, Martino, Warburton, Richard J. |
|---|---|
| Rok vydání: | 2023 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Mobile electrons in the semiconductor monolayer-MoS$_2$ form a ferromagnetic state at low temperature. The Fermi sea consists of two circles, one at the $K$-point, the other at the $\tilde{K}$-point, both with the same spin. Here, we present an optical experiment on gated MoS$_2$ 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, $\Sigma$, the energy required to flip a single spin within the ferromagnetic state, as well as the intervalley Coulomb exchange energy, $J$. We determine $\Sigma=11.2\,$meV and $J=5\,$meV at $n=1.5 \times 10^{12}\,$cm$^{-2}$, and find that $J$ depends strongly on the electron density, $n$. Comment: 13 pages, 11 figures |
| Databáze: | arXiv |
| Externí odkaz: |
|