Spin effects in the phase transition of the nuT = 1 bilayer electron system

K. MURAKI; P. GIUDICI; N. KUMADA

INTERNATIONAL JOURNAL OF MODERN PHYSICS B

WORLD SCIENTIFIC PUBL CO PTE LTD

Año: 2008 vol. 23 p. 2587 - 2595

0217-9792

We present tilted-field experiments on a bilayer electron system at νT = 1 with negligible tunneling and demonstrate that the spin degree of freedom plays a decisive role in the ground-state phase diagram of the system. We observe that the phase boundary separating the incompressible quantum Hall state and a compressible state at d/ℓB = 1.90 (d: interlayer distance, ℓB: magnetic length) in a perpendicular field shifts to higher densities with tilt until it saturates at d/ℓB = 2.33. We develop a model describing the energies of the competing phases and show that the observed shift of the phase boundary reflects the spin-polarization dependence of the Coulomb and Zeeman energies of the compressible state. A new phase diagram as a function of d/ℓB and the Zeeman energy is established and its implications as to the nature of the phase transition are discussed.