15 research outputs found
Spin resonance of 2D electrons in a large-area silicon MOSFET
We report electron spin resonance (ESR) measurements on a large-area silicon
MOSFET. An ESR signal at g-factor 1.9999(1), and with a linewidth of 0.6 G, is
observed and found to arise from two-dimensional (2D) electrons at the Si/SiO2
interface. The signal and its intensity show a pronounced dependence on applied
gate voltage. At gate voltages below the threshold of the MOSFET, the signal is
from weakly confined, isolated electrons as evidenced by the Curie-like
temperature dependence of its intensity. The situation above threshold appears
more complicated. These large-area MOSFETs provide the capability to
controllably tune from insulating to conducting regimes by adjusting the gate
voltage while monitoring the state of the 2D electron spins spectroscopically.Comment: 7 pages, 3 figures, submitted to Physica E special edition for
EPS2DS-1
Electron spin as a spectrometer of nuclear spin noise and other fluctuations
This chapter describes the relationship between low frequency noise and
coherence decay of localized spins in semiconductors. Section 2 establishes a
direct relationship between an arbitrary noise spectral function and spin
coherence as measured by a number of pulse spin resonance sequences. Section 3
describes the electron-nuclear spin Hamiltonian, including isotropic and
anisotropic hyperfine interactions, inter-nuclear dipolar interactions, and the
effective Hamiltonian for nuclear-nuclear coupling mediated by the electron
spin hyperfine interaction. Section 4 describes a microscopic calculation of
the nuclear spin noise spectrum arising due to nuclear spin dipolar flip-flops
with quasiparticle broadening included. Section 5 compares our explicit
numerical results to electron spin echo decay experiments for phosphorus doped
silicon in natural and nuclear spin enriched samples.Comment: Book chapter in "Electron spin resonance and related phenomena in low
dimensional structures", edited by Marco Fanciulli. To be published by
Springer-Verlag in the TAP series. 35 pages, 9 figure
Eseem of Orientationally Disordered-Systems .2. Lineshape Singularities in S=1/2, I=1 Systems with Small Quadrupole Interaction
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Electrical activation and spin coherence of ultra low dose antimony implants in silicon
Theory of the electron and nuclear spin coherence times of shallow donor spin qubits in isotopically and chemically purified zinc oxide
In this article, I present a theoretical study of the electron and nuclear spin coherence times of shallow donor spin qubits in zinc oxide (ZnO) at low temperature. The influence of different spin-phonon processes as well as different spin-spin processes on the spin coherence time of shallow donors in ZnO is considered, both in the case of an electron spin qubit and in the case of a nuclear spin qubit encoded on a shallow donor. It is estimated that the electron spin coherence time of an isolated indium shallow donor in natural quasi-intrinsic ZnO is on the order of hundreds of microseconds, limited by the nuclear spectral diffusion process. The electron spin coherence time of an isolated indium shallow donor can be extended to few milliseconds in isotopically and chemically purified quasi-intrinsic ZnO. In this optimal case, the electron spin coherence time of an isolated indium shallow donor is only limited by a spin-lattice decoherence process. It is also estimated that the nuclear spin coherence time of an isolated indium shallow donor in natural quasi-intrinsic ZnO is on the order of hundreds of milliseconds, limited by the nuclear spectral diffusion process. The nuclear spin coherence time of an isolated indium shallow donor can be extended to few seconds in isotopically and chemically purified quasi-intrinsic ZnO. In this optimal case, the nuclear spin coherence time of an isolated indium shallow donor is only limited by the cross relaxation decoherence process. This study thus shows the great potential of electron and nuclear spin qubits encoded on shallow donors in isotopically and chemically purified quasi-intrinsic ZnO for the implementation of quantum processor and/or quantum memories