title: Spin noise of electrons and holes in self-assembled quantum dots.
abstract: We measure the frequency spectra of random spin fluctuations, or "spin noise," in ensembles of (In,Ga)As/GaAs quantum dots (QDs) at low temperatures. We employ a spin noise spectrometer based on a sensitive optical Faraday rotation magnetometer that is coupled to a digitizer and field-programmable gate array, to measure and average noise spectra from 0-1 GHz continuously in real time with subnanoradian/sqrt[Hz] sensitivity. Both electron and hole spin fluctuations generate distinct noise peaks, whose shift and broadening with magnetic field directly reveal their g factors and dephasing rates within the ensemble. A large, energy-dependent anisotropy of the in-plane hole g factor is clearly exposed, reflecting systematic variations in the average QD confinement potential.
authors.affiliation: National High Magnetic Field Laboratory, Los Alamos, New Mexico 87545 USA. crooker@lanl.gov
authors.forename: S A
authors.initials: SA
authors.lastname: Crooker
authors.forename: J
authors.initials: J
authors.lastname: Brandt
authors.forename: C
authors.initials: C
authors.lastname: Sandfort
authors.forename: A
authors.initials: A
authors.lastname: Greilich
authors.forename: D R
authors.initials: DR
authors.lastname: Yakovlev
authors.forename: D
authors.initials: D
authors.lastname: Reuter
authors.forename: A D
authors.initials: AD
authors.lastname: Wieck
authors.forename: M
authors.initials: M
authors.lastname: Bayer