Wang Chengyu, Gupta A, Chung Y J, Pfeiffer L N, West K W, Baldwin K W, Winkler R, Shayegan M
Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, USA.
Department of Physics, Northern Illinois University, DeKalb, Illinois 60115, USA.
Phys Rev Lett. 2023 Aug 4;131(5):056302. doi: 10.1103/PhysRevLett.131.056302.
The even-denominator fractional quantum Hall states (FQHSs) in half-filled Landau levels are generally believed to host non-Abelian quasiparticles and be of potential use in topological quantum computing. Of particular interest is the competition and interplay between the even-denominator FQHSs and other ground states, such as anisotropic phases and composite fermion Fermi seas. Here, we report the observation of an even-denominator fractional quantum Hall state with highly anisotropic in-plane transport coefficients at Landau level filling factor ν=3/2. We observe this state in an ultra-high-quality GaAs two-dimensional hole system when a large in-plane magnetic field is applied. By increasing the in-plane field, we observe a sharp transition from an isotropic composite fermion Fermi sea to an anisotropic even-denominator FQHS. Our data and calculations suggest that a unique feature of two-dimensional holes, namely the coupling between heavy-hole and light-hole states, combines different orbital components in the wave function of one Landau level, and leads to the emergence of a highly anisotropic even-denominator fractional quantum Hall state. Our results demonstrate that the GaAs two-dimensional hole system is a unique platform for the exploration of exotic, many-body ground states.
通常认为，半填充朗道能级中的偶数分母分数量子霍尔态（FQHSs）包含非阿贝尔准粒子，并且在拓扑量子计算中具有潜在用途。特别令人感兴趣的是偶数分母FQHSs与其他基态之间的竞争和相互作用，例如各向异性相和复合费米子费米海。在此，我们报告了在朗道能级填充因子ν = 3/2时观察到具有高度各向异性面内输运系数的偶数分母分数量子霍尔态。当施加较大的面内磁场时，我们在超高质量的砷化镓二维空穴系统中观察到了这种状态。通过增加面内磁场，我们观察到从各向同性的复合费米子费米海到各向异性的偶数分母FQHS的急剧转变。我们的数据和计算表明，二维空穴的一个独特特征，即重空穴态和轻空穴态之间的耦合，将一个朗道能级波函数中的不同轨道分量结合起来，并导致出现高度各向异性的偶数分母分数量子霍尔态。我们的结果表明，砷化镓二维空穴系统是探索奇异多体基态的独特平台。
