Cascade of fractional quantum Hall states in 2D system
Chen Zhimou, Yan Jiaojie, Zhu Yuxuan, Cui Zhe, Pfeiffer Loren N. + 9 more
TLDR
New fractional quantum Hall states, including 17/33 and 15/31, are discovered in high-mobility GaAs/AlGaAs quantum wells, explained by composite fermion theory.
Key contributions
- Observed new FQH states at filling factors 17/33 and 15/31 in ultrahigh-quality GaAs/AlGaAs quantum wells.
- Systematically studied FQH states in 2D electron gases using quantum transport measurements down to 1 mK.
- Applied composite fermion theory to explain observed FQH states, including those from residual interactions.
- Proposed a pattern for FQH state appearance, offering insight into their relative strengths.
Why it matters
This research expands the known landscape of fractional quantum Hall states by identifying new ones in extremely high-quality samples. It provides a deeper understanding of strongly correlated topological phases. The proposed pattern offers a new framework for interpreting the relative strengths and appearance of these complex quantum phenomena.
Original Abstract
The observation of the fractional quantum Hall (FQH) effect in 2D electron gases ushered in investigations of topological phases driven by strong electron correlations. Their remarkable features include fractionalized elementary excitations, gapless boundary states, and non-trivial quantum entanglement patterns. Thanks to persistent efforts in the building of new platforms and making higher-quality samples, a diverse plethora of FQH states have been unveiled in experiments. We report a systematic study of ultrahigh-quality GaAs/AlGaAs quantum wells with mobility up to 3.7*10^7 cm^2/V/s using quantum transport measurements in nuclear adiabatic demagnetization and dilution refrigerators down to 1 mK. In addition to many FQH states that have already been identified in previous work, new longitudinal resistance dips are observed at filling factors 17/33 and 15/31. The application of an in-plane magnetic field causes disparate variations of the FQH states. The theoretical foundation of these states is discussed in the framework of composite fermion theory. While most fractions can be explained as non-interacting composite fermions forming integer quantum Hall states, a few states correspond to FQH states of composite fermions that arise from residual interaction between them. We summarize the observed fractions in the range of 0 < ν < 2 and propose a pattern to account for their experimental appearance that provides an intuitive picture about the relative strengths of different FQH states.
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