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Copyright Nature Publishing Group Jun 2015

Abstract

Valleytronics is rapidly emerging as an exciting area of basic and applied research. In two-dimensional systems, valley polarization 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 polarization. In stark contrast to expectations from a non-interacting model, we show experimentally that less magnetic field can be required to fully spin polarize a valley-polarized 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 crystalization, which in turn suggests the existence of a new strongly correlated electron liquid at low electron densities.

Details

Title
Valley polarization assisted spin polarization in two dimensions
Author
Renard, V T; Piot, B A; Waintal, X; Fleury, G; Cooper, D; Niida, Y; Tregurtha, D; Fujiwara, A; Hirayama, Y; Takashina, K
Pages
7230
Publication year
2015
Publication date
Jun 2015
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1684427785
Copyright
Copyright Nature Publishing Group Jun 2015