Landau-level crossing in two-subband systems in a tilted magnetic field

Duarte, Cesário Antônio; Gusev, G. M.; Quivy, A. A.; Lamas, T. E.; Bakarov, A. K.; Portal, J. C.

doi:10.1103/physrevb.76.075346

Cited by 24 publications

(20 citation statements)

References 22 publications

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“…Up to now, the T 1 results of the QHF formed at ν=2/3 [20] and at integers ν in a two-subband 2DEG (hereafter called two-subband QHF) [21,22] are suggestive of low energy DW excitations but exhibit different properties. Note that intricate CF-CF interactions at fractional ν (different from electron-electron interactions at integer ν) [23] and an additional degree of freedom associated with the subband index [24] may complicate the interpretation of these differences.…”

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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“…3 are 12 , 23 , and 13 . The effective g factor used in the calculations was determined by analysis of the Landau-level crossing diagram [14,35,36]. In the TQW studied here the Landau-level crossing observed in the perpendicular magnetic field yields an effective g factor of 13.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopic evidence of quantum Hall interlayer tunneling gap collapse caused by tilted magnetic field in a GaAs/AlGaAs triple quantum well

et al. 2014

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Magnetophotoluminescence and magnetotransport were studied in a GaAs/AlGaAs triple quantum well. Oscillations of the photoluminescence intensity observed in tilted magnetic fields were found to correspond to the interlayer tunneling quantum Hall gap collapses detected in magnetoresistance measurements and predicted to occur in tilted magnetic fields. The obtained experimental data were shown to agree well with the theory developed for double quantum wells. This implies that the observed quantum Hall gap collapses are mostly caused by the tunneling between a pair of quantum wells. Our results reveal spectroscopic evidence of the quantum Hall gap collapses. Indications of interlayer correlation effects influencing a character of the inter-Landau-level gaps were found.

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“…Exceptional attention has been paid to perpendicular magnetic fields, which leads to the integer [133] and fractional quantum Hall effects [134,135]. Although less attention has been given in the recent decades to in-plane or tilted magnetic fields, researchers have shown an increased interest (see, for instance, [109,111,[136][137][138][139][140][141][142][143][144]). For example, in Refs.…”

Section: Absence Of Effects Of An In-plane Magnetic Field In a Q2desmentioning

confidence: 99%

Teoria quântica em uma subvariedade: Efeitos clássicos, quânticos e térmicos

Monroy¹

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The problem of how to describe the effective dynamics of particles or fields confined to a lower dimensional curved space-time is of interest in many areas of physics. In the literature, several methods have been proposed to attack this problem. Recently it has been reported some experimental evidences that are consistent with the so-called confining potential approach. In light of these results, the purpose of this thesis is to construct a quantum theory for particles confined in a submanifold of a flat space-time employing the theoretical framework of the confining potential approach. The thesis is divided into two parts. The first one is dedicated exclusively to the study of quantum mechanics on a submanifold. For this purpose, we derive the effective Schrödinger, Dirac and Klein-Gordon equations on a curved submanifold, in the presence of an external electromagnetic field. We examine the singular features of these equations and present some applications to condensed matter. In the second part of this thesis, we start from the quantum mechanics on the submanifold and then we formulate the quantum field theory (QFT) on the submanifold. We will show that the "free" QFT on a submanifold can be schematically represented as a quantum theory of free fields on a curved background plus a scalar potential and an external SO(n − m) Yang-Mills field. For this theory, we compute the one-loop effective action for scalars and fermions at finite temperature and chemical potential to all orders using the Seely-DeWitt expansion. For interacting theories, we will prove that the theory known as reduced quantum electrodynamics (RQED dγ ,de) can be recovered from the confining potential approach. For a two-dimensional theory, we propose a large class of extensions of the Schwinger model, in which the interaction between fermions goes beyond the linear potential. We demonstrate that, remarkably, these extensions are exactly solvable for massless fermions and that there is no dynamical mass generation for the fermions. Furthermore, we construct a new family of exactly bosonized theories. We also show that RQED 4,2 has the necessary features to be identified as an effective field theory for graphene wires. Finally, we study the effect of an interplay of real and pseudomagnetic fields in graphene. We compute the fermion condensate, the induced vacuum charge density, the one-loop effective action and the magnetization, for this system. We will show that the presence of a non-zero pseudomagnetic field makes it possible, experimentally, to observe an induced vacuum charge density. Moreover, we will show that it is possible to have control over the magnetization as well as the dynamical mass for each valley in graphene, by straining or varying the applied magnetic field.

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Landau-level crossing in two-subband systems in a tilted magnetic field

Cited by 24 publications

References 22 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

Spectroscopic evidence of quantum Hall interlayer tunneling gap collapse caused by tilted magnetic field in a GaAs/AlGaAs triple quantum well

Teoria quântica em uma subvariedade: Efeitos clássicos, quânticos e térmicos

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