Zeeman splitting of excitons in CdTe/CdMnTe quantum wells

AbstractWe have observed nuclear magnetic resonance (NMR) signatures from constituent Ga and As nuclei in single GaAs quantum dots formed by interface fluctuations in GaAs/AlGaAs quantum wells. Orientation of the nuclear spin system by optical pumping causes an Overhauser shift in the excitonic energy levels proportional to the degree of nuclear orientation. NMR was detected by monitoring changes in the combined Overhauser plus Zeeman splitting of an exciton localized in a single quantum dot as the RF frequency was swept through a nuclear resonance. The NMR signals originate from ∼105 nuclei in the quantum dot — (20 nm)3 volume - representing an increase in sensitivity of five orders of magnitude over previous optical NMR measurements and thirteen orders of magnitude over conventional NMR. The data were fit to Lorentzian lineshapes, giving 75As linewidths on the order of 20 kHz.

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Zeeman splitting andgfactor of heavy-hole excitons inInxGa1−xAs/GaAs quantum wells

Physical Review B ◽

10.1103/physrevb.51.7361 ◽

1995 ◽

Vol 51 (11) ◽

pp. 7361-7364 ◽

Cited By ~ 44

Author(s):

N. J. Traynor ◽

R. T. Harley ◽

R. J. Warburton

Keyword(s):

Quantum Wells ◽

Heavy Hole ◽

Zeeman Splitting

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VALLEY SPLITTING AND g-FACTOR IN AlAs QUANTUM WELLS

International Journal of Modern Physics B ◽

10.1142/s0217979209062608 ◽

2009 ◽

Vol 23 (12n13) ◽

pp. 2948-2954

Author(s):

C. A. DUARTE ◽

G. M. GUSEV ◽

T. E. LAMAS ◽

A. K. BAKAROV ◽

J.-C. PORTAL

Keyword(s):

Magnetic Field ◽

Quantum Wells ◽

Quantum Confinement ◽

Zeeman Splitting ◽

Exchange Contribution ◽

G Factor ◽

Valley Splitting ◽

Perpendicular Component ◽

Magneto Resistance ◽

The Magnetic Field

Here we present the results of magneto resistance measurements in tilted magnetic field and compare them with calculations. The comparison between calculated and measured spectra for the case of perpendicular fields enable us to estimate the dependence of the valley splitting as a function of the magnetic field and the total Landé g -factor (which is assumed to be independent of the magnetic field). Since both the exchange contribution to the Zeeman splitting as well as the valley splitting are properties associated with the 2D quantum confinement, they depend only on the perpendicular component of the magnetic field, while the bare Zeeman splitting depends on the total magnetic field. This information aided by the comparison between experimental and calculated gray scale maps permits to obtain separately the values of the exchange and the bare contribution to the g -factor.

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