Real-space imaging of fractional quantum Hall liquids

Hayakawa, Junichiro; Muraki, K.; Yusa, Go

doi:10.1038/nnano.2012.209

Cited by 43 publications

(53 citation statements)

References 30 publications

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“…The quantum Hall ferromagnet (QHF) formed at two energetically-degenerate spin-resolved Landau levels (LLs) in a two-dimensional electron gas (2DEG) has provided an ideal system for understanding itinerant electron ferromagnetism, spin interactions, and domain dynamics [1][2][3][4][5][6][7][8][9][10][11][12][13]. In particular, a resistively detected nuclear magnetic resonance (RDNMR) technique developed in the QHF of GaAs 2DEGs at filling factor ν=2/ 3 (corresponding to a composite-fermion (CF) filling factor ν CF =2) has been widely used to investigate the dynamic nuclear polarization (DNP) in semiconductors [14,15], to coherently control the nuclear spins in the 2DEG [16], and to discover exotic electron phases in quantum Hall systems [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Pump-probe nuclear spin relaxation study of the quantum Hall ferromagnet at filling factor ν = 2

et al. 2019

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The nuclear spin-lattice relaxation time T 1 of the ν=2 quantum Hall ferromagnet (QHF) formed in a gate-controlled InSb two-dimensional electron gas has been characterized using a pump-probe technique. In contrast to a long T 1 of quantum Hall states around ν=1 that possesses a Korringatype temperature dependence, the temperature-independent short T 1 of the ν=2 QHF suggests the presence of low energy collective spin excitations in a domain wall. Furthermore, T 1 of this ferromagnetic state is also found to be fillingand current-independent. The interpretation of these results as compared to the T 1 properties of other QHFs is discussed in terms of the domain wall skyrmion, which will lead to a better understanding of the QHF.

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Section: Introductionmentioning

confidence: 99%

Pump-probe nuclear spin relaxation study of the quantum Hall ferromagnet at filling factor ν = 2

et al. 2019

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“…The finite width corrections should be negligible in graphene. We note that extensive investigation of the spin or valley physics of the FQHE states of the form ν = n/(2n ± 1) has been performed experimentally in GaAs and AlAs quantum wells as well as graphene [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] and these results have been analyzed quantitatively by the CF theory [54][55][56]. One may wonder about the role of CF skyrmions; these are estimated to be relevant only for very small values of κ < 0.007 close to ν = 1/3 [57], but are not relevant for the physics of the ground state at 3/8 [54].…”

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confidence: 99%

Possible realization of a chiralp-wave paired state in a two-component system

2014

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There is much interest in the realization of systems with p-wave pairing in one dimension or chiral p-wave pairing in two dimensions, because these are believed to support Majorana modes at the ends or inside vortices. We consider a two component system of composite fermions and provide theoretical evidence that, under appropriate conditions, the screened interaction between the minority composite fermions is such as to produce an almost exact realization of p-wave paired state described by the so-called anti-Pfaffian wave function. This state is predicted to occur at filling ν = 3/8 or 13/8 in GaAs when the Zeeman energy is sufficiently small, and at ν = ±3/8 or ±13/8 in single layer graphene when either the Zeeman or the valley splitting is sufficiently small.

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“…The disorder potential strongly modulates the QH IC phase, providing sharply different microscopic perspectives for different mobility samples. This work can be extended to study the microscopic influences of potential disorder on fractional quantum Hall (FQH) IC strips and IC domain structures [12].…”

Section: Pacs Numbers: Valid Pacs Appear Herementioning

confidence: 99%

Real space imaging of the quantum-Hall incompressible states influenced by the strong disorder

Wang

Hashimoto

Hirayama

2019

2019 Compound Semiconductor Week (CSW)

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While the disorder-induced quantum Hall (QH) effect has been studied previously, the effect of disorder potential on microscopic features of the integer QH effect remains unclear, particularly for the incompressible (IC) strip. In this research, a scanning gate microscope incorporated with the non-equilibrium transport technique is used to study the influence of potential disorder on the QH IC strip emerging near the sample edge. It was found that different mobility samples with different disorder potentials showed the same spatial dependence of the IC strip on the filling factor, while in the low-mobility sample alone, strong pattern modulations such as bright and dark spots appeared in the IC strip. This pattern is related to the stronger potential disorder inherent to the low-mobility sample. It could be concluded that this disorder strongly affects the QH state, and the applied technique can be effectively used to detect the IC strip in a low-mobility sample. PACS numbers: Valid PACS appear hereUnder a strong magnetic field, two-dimensional electron gas (2DEG) forms quantum Hall (QH) phases, such as insulating incompressible (IC) and metallic compressible (C) phases. The microscopic configuration of these phases, determined by both the nonlinear screening effect and electrostatic potential landscape in the 2DEG plane, plays an essential role for the QH effect. When the filling factor (ν) is close to the integer ν, the IC region covering the interior of the 2DEG protects the counter propagating C edge channels from backscattering in between the channels [1]. The bulk IC phase emerges owing to potential disorder at ν, deviating slightly from the exact integer ν, inducing the quantized Hall conductance that is widely persistent around an integer ν. This disorder-induced QH effect has been microscopically confirmed through scanning probe measurement [2, 3] that showed compressible paddles interspersed with the IC bulk phase, namely, localized states. On the other hand, the IC along the edge of the 2DEG governed by edge confinement potential [4] and its robust ν-dependence have recently been microscopically demonstrated for the high mobility Hall bar device by our nonequilibrium-transport assisted scanning gate imaging [5].While the disorder stabilizes integer QH effect, further strong disorder may significantly disturb the QH state. The localized states in the integer QH effect may be delocalized owing to disorder scattering [6]. When the disorder strength is sufficiently high, QH plateaus begin to collapse and finally cease the existence of the integer QH effect [6]. However, it is not clear how disorder potential disturbs microscopic features of the integer QH effect, particularly for the IC strip and its movement. In this study, we address influence of potential disorder on the IC strips in GaAs quantum wells with the different mobility samples. To the end, a non-equilibrium transport assisted scanning probe technique, which was previous (b) (c) (a) ΔV xx (μV) ν = 1.07 48 -30 0.02 0.00 2 μm ν = 1.07 25 -23 0.0...

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Real-space imaging of fractional quantum Hall liquids

Cited by 43 publications

References 30 publications

Pump-probe nuclear spin relaxation study of the quantum Hall ferromagnet at filling factor ν = 2

Pump-probe nuclear spin relaxation study of the quantum Hall ferromagnet at filling factor ν = 2

Possible realization of a chiralp-wave paired state in a two-component system

Real space imaging of the quantum-Hall incompressible states influenced by the strong disorder

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