TY - JOUR
T1 - Finite-thickness effect and spin polarization of the even-denominator fractional quantum Hall states
AU - Wang, Pengjie
AU - Sun, Jian
AU - Fu, Hailong
AU - Wu, Yijia
AU - Chen, Hua
AU - Pfeiffer, L. N.
AU - West, K. W.
AU - Xie, X. C.
AU - Lin, Xi
N1 - Publisher Copyright:
© 2020 authors. Published by the American Physical Society.
PY - 2020/6
Y1 - 2020/6
N2 - The spin-polarized even-denominator fractional quantum Hall (FQH) states in the second Landau level (LL), i.e., 5/2 and 7/2, may possess novel quasiparticle excitations obeying non-Abelian statistics. However, the spin polarization of the 7/2 FQH state has not been investigated experimentally and the spin polarization of the 5/2 FQH state from tilted-field experiments remains controversial. Using a piezodriven sample rotator with the lowest electron temperature down to 25 mK, we studied the energy gap of the even-denominator FQH states in the second LL by precise control of the tilted angles with a resolution less than 0.1°. We observed two different energy gap dependences on the in-plane magnetic field for 5/2, 7/2, other FQH states (7/3 and 8/3) in the second LL, and reentrant integer quantum Hall (RIQH) states in the third LL. Though the transition fields vary from states, their corresponding in-plane magnetic lengths are comparable to the quantum well thickness of the sample, which may result from the influence of the finite-thickness effect. At low in-plane magnetic fields, before the conjectured finite-thickness effect starts to dominate, the energy gaps of both 5/2 and 7/2 states show a nondecreasing behavior, supporting spin-polarized ground states. Our results also suggest that the 7/3, 8/3 FQH states, and the RIQH states in the third LL are spin polarized or partially spin polarized.
AB - The spin-polarized even-denominator fractional quantum Hall (FQH) states in the second Landau level (LL), i.e., 5/2 and 7/2, may possess novel quasiparticle excitations obeying non-Abelian statistics. However, the spin polarization of the 7/2 FQH state has not been investigated experimentally and the spin polarization of the 5/2 FQH state from tilted-field experiments remains controversial. Using a piezodriven sample rotator with the lowest electron temperature down to 25 mK, we studied the energy gap of the even-denominator FQH states in the second LL by precise control of the tilted angles with a resolution less than 0.1°. We observed two different energy gap dependences on the in-plane magnetic field for 5/2, 7/2, other FQH states (7/3 and 8/3) in the second LL, and reentrant integer quantum Hall (RIQH) states in the third LL. Though the transition fields vary from states, their corresponding in-plane magnetic lengths are comparable to the quantum well thickness of the sample, which may result from the influence of the finite-thickness effect. At low in-plane magnetic fields, before the conjectured finite-thickness effect starts to dominate, the energy gaps of both 5/2 and 7/2 states show a nondecreasing behavior, supporting spin-polarized ground states. Our results also suggest that the 7/3, 8/3 FQH states, and the RIQH states in the third LL are spin polarized or partially spin polarized.
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U2 - 10.1103/PhysRevResearch.2.022056
DO - 10.1103/PhysRevResearch.2.022056
M3 - Article
AN - SCOPUS:85115897396
SN - 2643-1564
VL - 2
JO - Physical Review Research
JF - Physical Review Research
IS - 2
M1 - 022056
ER -