Competition between a Fractional Quantum Hall Liquid and Bubble and Wigner Crystal Phases in the Third Landau Level

Abstract

Magnetotransport measurements were performed in an ultrahigh mobility GaAs/AlGaAs quantum well of density approximately 3.0 x 10(11) cm(-2). The temperature dependence of the magnetoresistance Rxx was studied in detail in the vicinity of nu=9/2. In particular, we discovered new minima in Rxx at a filling factor nu approximately 41/5 and 44/5, but only at intermediate temperatures 80 approximately less than T approximately less than 120 mK. We interpret these as evidence for a fractional quantum Hall liquid forming in the N=2 Landau level and competing with bubble and Wigner crystal phases favored at lower temperatures. Our data suggest that a magnetically driven insulator-insulator quantum phase transition occurs between the bubble and Wigner crystal phases at T=0.

Competing Fractional Quantum Hall and Electron Solid Phases in Graphene

“…In addition to the RIQHE states, we observe signatures of weakly developed FQHE states at ν = 6 + 1/5, 6 + 4/5, 7 + 1/5, and 7 + 4/5 in the form of σ xx minima simultaneous with kinks in the Hall conductivity (though not showing clear plateaus). Similar FQHE states have been previously reported in the third LL of ultra-high mobility GaAs/AlGaAs samples [13]. Finally, we note that there is a clear absence of the 1/3 FQHE states, which are the dominant FQHE states appearing in both N=0 and N=1 orbital branches of monolayer graphene [35,36](also see supplementary information).…”

“…One of the most widely studied examples is the fractional quantum Hall effect (FQHE) [1][2][3][4], an incompressible liquid that emerges when the lowest energy Landau levels (LLs) are partially filled. However, the incompressible FQHE liquids are not the only correlated phases that can emerge within partially filled LLs and generically compete with the formation of interaction-driven electron solids, such as the Wigner crystal [5][6][7][8], and the bubble [9][10][11][12][13][14][15][16][17][18] and stripe charge density wave states [9,11,12,16,17,19].In GaAs/AlGaAs heterostructures, the competition between these different phases, particularly developed in the N = 1 and 2 LL, gives rise to a reentrant integer quantum Hall effect (RIQHE) [14,[20][21][22][23]. This is characterized by the emergence of vanishing longitudinal resistance at fractional filling between the usual sequence of FQHE states, but with Hall conductivity restored to the closest integer value.…”

Microwave spectroscopic observation of distinct electron solid phases in wide quantum wells

“…At the highest n , the peak vanishes as the RIQHE minimum merges with the main IQHE minimum. This peak in R xx could be produced by domain-wall conduction at a phase transition1723.…”

Quantum Entanglement as a Diagnostic of Phase Transitions in Disordered Fractional Quantum Hall Liquids

“…However, unlike the dramatic phase-transition signal in the entanglement entropy derivative, we find a gradual reduction of level repulsion only deep in the Anderson insulating phase. Introduction.-Following the advances in understanding the fascinatingly complex phase diagram of two-dimensional electron systems in a strong perpendicular magnetic field in the fractional quantum Hall (FQH) regime [1][2][3][4][5][6][7][8][9][10][11][12], there has been intense interest in phase transitions in topological systems [13][14][15][16][17]. Disorder is a ubiquitous ingredient that may affect, even drive such phase transitions.…”