Activation energy gap of the layer-imbalanced bilayer nu=1/3 quantum Hall states

作者：Fukuda A^*; Sekikawa T; Iwata K; Ogasawara Y; Arai T; Ezawa Z F; Sawada A

来源：Physica E: Low-Dimensional Systems and Nanostructures , 2010, 42(4): 1046-1049.

DOI：10.1016/j.physe.2009.10.013

• Fractional quantum Hall effect
• Composite fermion
• Bilayer
• Commensurate-incommensurate phase transition
• Activation energy
• Layer density imbalance
• Pseudospin

We investigate the bilayer fractional quantum Hall state (FQHS) in layer-imbalanced configurations at the total Landau level filling factor nu = 1/3 which is interpreted as the bilayer nu = 1 integer quantum Hall state (IQHS) of composite fermions (CFs). We carried out detailed magnetotransport experiments, especially focused on measurements of the activation energy gap Lambda in the bilayer nu = 1/3 FQHS under tilted magnetic fields. We observed Lambda as a function of in-plane magnetic field for various layer density imbalance parameters sigma, which is compared with the reported data of the bilayer nu =1 IQHS. At small sigma, the FQHSs collapse by applying large in-plane fields. This behavior is interpreted as the transition from the commensurate (C)-like phase to no-FQHS. At large sigma, Delta stays finite even in large in-plane field, which means the incommensurate (IC)-like phase appears also in the nu = 1/3 layer-imbalanced bilayer FQHS. We discuss the interactions among CFs from the phase transition point between the C-like and the IC-like phases in the layer-imbalanced nu = 1/3 FQHS.

• 出版日期2010-2