Spin-noise in the anisotropic central spin model
| Autor: | Johannes Hackmann, Frithjof B. Anders |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Physics
Larmor precession Condensed matter physics Condensed Matter - Mesoscale and Nanoscale Physics FOS: Physical sciences Condensed Matter Physics Noise (electronics) Spectral line Electronic Optical and Magnetic Materials Quantum dot Quantum mechanics Thermodynamic limit Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Spin model Ising model Spin-½ |
| Popis: | Spin-noise measurements can serve as direct probe for the microscopic decoherence mechanism of an electronic spin in semiconductor quantum dots (QD).We have calculated the spin-noise spectrum in the anisotropic central spin model using a Chebyshev expansion technique which exactly accounts for the dynamics up to an arbitrary long but fixed time in a finite size system. In the isotropic case, describing QD charged with a single electron, the short-time dynamics is in good agreement with a quasi-static approximation for the thermodynamic limit. The spin-noise spectrum, however, shows strong deviations at low frequencies with a power-law behavior. In the Ising limit, applicable to QDs with heavy-hole spins, the spin-noise spectrum exhibits a threshold behavior above the Larmor frequency. In the generic anisotropic central spin model we have found a crossover from a Gaussian type of spin-noise spectrum to a more Ising-type spectrum with increasing anisotropy in a finite magnetic field. In order to make contact with experiments, we present ensemble averaged spin-noise spectra for QD ensembles charged with single electrons or holes. The Gaussian-type noise spectrum evolves to a more Lorentzian shape spectrum with increasing spread of characteristic time-scales and g-factors of the individual QDs. 24 pages, 16 figures, submitted to PRB |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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