Magnetization of bilayer two-dimensional electron systems

Bominaar-Silkens, I. M. A.; Schaapman, M.R.; Zeitler, U.; Christianen, P.C.M.; Maan, J.C.; Reuter, D.; Wieck, A. D.; Schuh, Dieter; Bichler, Max

doi:10.1088/1367-2630/8/12/315

Cited by 5 publications

(6 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The overshoots do not depend on the field sweep direction. Similar effects were reported for a bi-layered 2DES in GaAs/AlGaAs [33]. The authors speculated that correlations effects or a peculiar form of the DOS were responsible for the overshoot.…”

Section: B (T)supporting

confidence: 73%

Enhanced quantum oscillatory magnetization and nonequilibrium currents in an interacting two-dimensional electron system in MgZnO/ZnO with repulsive scatterers

et al. 2014

View full text Add to dashboard Cite

Torque magnetometry at low temperature and in high magnetic fields B is performed on a MgZnO/ZnO heterostructure incorporating a high-mobility two-dimensional electron system. We find a sawtooth-like quantum oscillatory magnetization M (B), i.e., the de Haas-van Alphen (dHvA) effect. At the same time, unexpected spike-like overshoots in M and non-equilibrium currents are observed which allow us to identify the microscopic nature and density of the residual disorder. The acceptor-like scatterers give rise to a magnetic thaw down effect which enhances the dHvA amplitude beyond the electron-electron interaction effects being present in the MgZnO/ZnO heterostructure. PACS numbers: Valid PACS appear hereOxide heterostructures have generated tremendous interest in recent years [1,2]. Two-dimensional electron systems (2DESs) formed therein exhibit remarkable properties such as superconductivity [3] and magnetism [4] or the fractional quantum Hall effect (QHE) [5,6]. MgZnO/ZnO-based heterostructures are outstanding in that 2DESs of small carrier density n s exhibit extremely high mobilities µ at low temperature T [5,6]. At the same time, the electron-electron interaction parameter r s ∝ n −0.5 s [7] is large allowing for electron correlation effects at oxide interfaces in an applied magnetic field B [6,8,9]. Still, the quantum oscillatory magnetization M (B), i.e., the de Haas-van Alphen (dHvA) effect reflecting the ground state properties of such 2DESs has not yet been explored. Since the discovery of the dHvA effect in Bi more than eight decades ago it has been argued that disorder reduces peak-to-peak amplitudes ∆M via broadening of the quantized Landau levels E j (j = 0, 1, 2, ...) [10][11][12]. In contrast, electron-electron interaction effects are known to enhance ∆M [13]. The two counteracting effects are however not easy to distinguish in a balancing situation. Sometimes the dHvA effect has been obscured in the QHE regime even completely by extremely large non-equilibrium currents (NECs) [14]. The NECs are induced near integer filling factors ν = hn s /(eB ⊥ ) at low T when the longitudinal resistivity ρ xx takes a vanishingly small value and are believed to be limited only by breakdown of the QHE [14]. Independent transport experiments on GaAs-based heterostructures have evidenced that, strikingly, minima in ρ xx and plateaus in the Hall resistivity ρ xy could be displaced away from integer ν towards smaller ν due to repulsive scatterers [15][16][17][18][19]. This phenomenon has not yet been resolved in M (B), and a clear experimental manifestation of the underlying asymmetric density of states (DOS) in a ground state property is still lacking.In this Letter, we report torque magnetometry on the equilibrium dHvA effect and NECs of a high-mobility 2DES residing at a MgZnO/ZnO heterointerface. We observe dHvA amplitudes ∆M at filling factors ν = 1 and 2 that are significantly enhanced over the expected values in the single-particle picture. Addressing a regime 0.28 K < T < 1.6 K we observe T -dependent shifts of ...

show abstract

Section: B (T)supporting

confidence: 73%

Enhanced quantum oscillatory magnetization and nonequilibrium currents in an interacting two-dimensional electron system in MgZnO/ZnO with repulsive scatterers

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Optical detection turned out to be workable even for measurements in the field of Bitter magnet, which creates a fairly large electrical noise. In this case, the threshold sensitivity was albeit lower by an order of magnitude, but still was enough for studying quantum oscillations of magnetization single- [16] and double-layer heterojunctions GaAs/AlGaAs [15].…”

Section: Torsion Magnetometers With Optical Detectionmentioning

confidence: 99%

“…In Refs. [14,15], an optical technique was used for sample deviations detecting. For this purpose, a laser beam was introduced into a cryostat via a multimode fiber, reflected from the sample and then reached photodetector.…”

Section: Torsion Magnetometers With Optical Detectionmentioning

confidence: 99%

Measurements of the magnetic properties of conduction electrons

Pudalov

2021

Phys.-Usp.

View full text Add to dashboard Cite

We consider various methods and techniques for measuring electron magnetization and susceptibility, which are used in experimental condensed matter physics. The list of considered methods for macroscopic measurements includes magnetomechanic, electromagnetic, modulation-type, and also thermodynamic methods based on the chemical potential variation measurements. We also consider local methods of magnetic measurements based on the spin Hall effects, NV-centers. Several scanning probe magnetometers-microscopes are considered, such as magnetic resonance force microscope, SQUID-microscope, and Hall microscope. The review focuses on the spin magnetization measurements of electrons in non-magnetic materials and artificial systems, particularly, in lowdimensional electron systems in semiconductors and in nanosystems, which came to the forefront in recent years.

show abstract

“…9,28,29 These gaps are called thermodynamic energy gaps to distinguish them on the one hand from gaps obtained by excitation spectroscopy where selection rules must be considered. Rules such as the generalized Kohn's theorem might obscure electron-electron interaction effects.…”

Section: A Data Analysismentioning

confidence: 99%

De Haas-van Alphen effect and energy gaps of a correlated two-dimensional electron system in an AlAs two-valley pseudospin system

et al. 2009

View full text Add to dashboard Cite

We report highly sensitive de Haas-van Alphen ͑dHvA͒ effect measurements on a high-mobility twodimensional electron system in an AlAs quantum well. Here two valleys are occupied forming a pseudospin system. At 400 mK, the dHvA effect shows pronounced oscillations at filling factors = 1 to four. In the quantum limit at = 1 the data are consistent with an interaction-enhanced valley splitting, which exceeds the Zeeman spin splitting in a perpendicular field B. When tilting B the energy gap ⌬E at = 1 shows first an unexpectedly strong angular dependence and then remains constant. This suggests a crossover in the energy gap, most likely from a spin to a pseudospin gap. We attribute the strong initial dependence of ⌬E on the tilt angle to skyrmion-type spin excitations. Surprisingly, the dHvA oscillation amplitudes do not display coincidence phenomena at higher filling factors. This is explained by the large valley splitting and avoided crossings of energy levels.

show abstract

Magnetization of bilayer two-dimensional electron systems

Cited by 5 publications

References 15 publications

Enhanced quantum oscillatory magnetization and nonequilibrium currents in an interacting two-dimensional electron system in MgZnO/ZnO with repulsive scatterers

Enhanced quantum oscillatory magnetization and nonequilibrium currents in an interacting two-dimensional electron system in MgZnO/ZnO with repulsive scatterers

Measurements of the magnetic properties of conduction electrons

De Haas-van Alphen effect and energy gaps of a correlated two-dimensional electron system in an AlAs two-valley pseudospin system

Contact Info

Product

Resources

About