Valley splitting of Si/SiGe heterostructures in tilted magnetic fields

Abstract

We have investigated the valley splitting of two-dimensional electrons in high quality Si/Si${}_{1-x}$Ge${}_x$ heterostructures under tilted magnetic fields. For all the samples in our study, the valley splitting at filling factor $\nu =3$ (${\Delta }_3$) is significantly different before and after the coincidence angle, at which energy levels cross at the Fermi level. On both sides of the coincidence, a linear density dependence of ${\Delta }_3$ on the electron density was observed, while the slope of these two configurations differs by more than a factor of two. We argue that screening of the Coulomb interaction from the low-lying filled levels, which also explains the observed spin-dependent resistivity, is responsible for the large difference of ${\Delta }_3$ before and after the coincidence.

arXiv commentREVTEX 4 pages, 4 figures

References in corpus (5)

• Valley splitting of AlAs two-dimensional electrons in a perpendicular magnetic field
• Canted antiferromagnetic phase in a double quantum well in a tilted quantizing magnetic field
• Strong enhancement of the valley splitting in a 2D electron system in silicon
• Observation of Inter-Valley Gap Anomaly of Two Dimensional electrons in Silicon
• Spin-dependent resistivity at transitions between integer quantum Hall states

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