title: Intervalley gap anomaly of two-dimensional electrons in silicon.
abstract: We report here a systematic study of the energy gaps at the odd-integer quantum Hall states nu = 3 and 5 under tilted magnetic (B) fields in a high quality Si two-dimensional electron system. Out of the coincidence region, the valley splitting is independent of the in-plane fields. However, the nu = 3 valley gap differs by about a factor of 3 (Deltav approximately 0.4 vs 1.2 K) on different sides of the coincidence. More surprisingly, instead of reducing to zero, the energy gaps at nu = 3 and 5 rise rapidly when approaching the coincidence angles. We believe that such an anomaly is related to strong couplings of the nearly degenerate Landau levels.
authors.affiliation: Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: K
authors.initials: K
authors.lastname: Lai
authors.forename: W
authors.initials: W
authors.lastname: Pan
authors.forename: D C
authors.initials: DC
authors.lastname: Tsui
authors.forename: S
authors.initials: S
authors.lastname: Lyon
authors.forename: M
authors.initials: M
authors.lastname: Mühlberger
authors.forename: F
authors.initials: F
authors.lastname: Schäffler