Phys. Rev. Lett. 87, 136801 (2001) [4 pages]New Phase Transition between Partially and Fully Polarized Quantum Hall States with Charge and Spin Gaps at ν = 2/3Received 30 May 2001; published 7 September 2001 The average electron spin polarization P of a two-dimensional electron gas confined in GaAs/GaAlAs multiple quantum wells was measured by NMR near the fractional quantum Hall state with filling factor ν = 2/3. Above this filling factor ( 2/3≤ν<0.85), a strong depolarization is observed corresponding to two spin flips per additional flux quantum. The most remarkable behavior of the polarization is observed at ν = 2/3, where a quantum phase transition from a partially polarized ( P≈3/4) to a fully polarized ( P = 1) state can be driven by increasing the ratio between the Zeeman and the Coulomb energy above a critical value ηc = ΔZ/ΔC = 0.0185. © 2001 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.87.136801
DOI:
10.1103/PhysRevLett.87.136801
PACS:
73.43.Nq, 71.10.-w, 76.60.Cq
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