Abstract : Valleytronics is rapidly emerging as an exciting area of basic and applied research. In two dimensional systems, valley polarisation can dramatically modify physical properties through electron-electron interactions as demonstrated by such phenomena as the fractional quantum Hall effect and the metal-insulator transition. Here, we address the electrons' spin alignment in a magnetic field in silicon-on-insulator quantum wells under valley polarisation. In stark contrast to expectations from a non-interacting model, we show experimentally that less magnetic field can be required to fully spin polarise a valley-polarised system than a valley-degenerate one. Furthermore, we show that these observations are quantitatively described by parameter free ab initio quantum Monte Carlo simulations. We interpret the results as a manifestation of the greater stability of the spin and valley degenerate system against ferromagnetic instability and Wigner crystalisation which in turn suggests the existence of a new strongly correlated electron liquid at low electron densities.
https://hal.archives-ouvertes.fr/hal-01160304
Contributeur : Vincent Renard <>
Soumis le : vendredi 5 juin 2015 - 09:32:37
Dernière modification le : samedi 18 février 2017 - 01:16:34
Document(s) archivé(s) le : mardi 25 avril 2017 - 03:15:21
V.T. Renard, B. A. Piot, X Waintal, G Fleury, D Cooper, et al.. Valley polarization assisted spin polarization in two dimensions. Nature Communications, Nature Publishing Group, 2015, 6, pp.7230. <10.1038/ncomms8230>. <hal-01160304>
