The description of nuclear spin systems using a thermal state with a well
defined nuclear spin temperature has had tremendous success in explaining a
variety of experimental observations on solid-state nuclear spin systems. Using
demagnetization experiments we demonstrate that the mesoscopic nuclear spin
ensemble of a quantum dot can in general not be described by a spin
temperature, even for observation time-scales exceeding minutes. We associate
the striking deviations from a thermal spin state with the presence of strong
quadrupolar interactions within the quantum dot. Strain-induced, inhomogeneous
quadrupolar shifts with position dependent axes result in a breakdown of
adiabaticity during magnetic field sweeps and thereby cause an irreversible
loss of nuclear spin polarization. At the same time, quadrupolar interactions
lead to a complete suppression of angular momentum exchange between the nuclear
spin ensemble and its environment, resulting in nuclear spin relaxation times
on the order of hours.
Description
Demagnetization of Quantum Dot Nuclear Spins: Breakdown of the Nuclear
Spin Temperature Approach
%0 Generic
%1 Maletinsky2009
%A Maletinsky, P.
%A Kroner, M.
%A Imamoglu, A.
%D 2009
%K dot experiment hyperfine nuclear quantum spins
%T Demagnetization of Quantum Dot Nuclear Spins: Breakdown of the Nuclear
Spin Temperature Approach
%U http://arxiv.org/abs/0901.2289
%X The description of nuclear spin systems using a thermal state with a well
defined nuclear spin temperature has had tremendous success in explaining a
variety of experimental observations on solid-state nuclear spin systems. Using
demagnetization experiments we demonstrate that the mesoscopic nuclear spin
ensemble of a quantum dot can in general not be described by a spin
temperature, even for observation time-scales exceeding minutes. We associate
the striking deviations from a thermal spin state with the presence of strong
quadrupolar interactions within the quantum dot. Strain-induced, inhomogeneous
quadrupolar shifts with position dependent axes result in a breakdown of
adiabaticity during magnetic field sweeps and thereby cause an irreversible
loss of nuclear spin polarization. At the same time, quadrupolar interactions
lead to a complete suppression of angular momentum exchange between the nuclear
spin ensemble and its environment, resulting in nuclear spin relaxation times
on the order of hours.
@misc{Maletinsky2009,
abstract = { The description of nuclear spin systems using a thermal state with a well
defined nuclear spin temperature has had tremendous success in explaining a
variety of experimental observations on solid-state nuclear spin systems. Using
demagnetization experiments we demonstrate that the mesoscopic nuclear spin
ensemble of a quantum dot can in general not be described by a spin
temperature, even for observation time-scales exceeding minutes. We associate
the striking deviations from a thermal spin state with the presence of strong
quadrupolar interactions within the quantum dot. Strain-induced, inhomogeneous
quadrupolar shifts with position dependent axes result in a breakdown of
adiabaticity during magnetic field sweeps and thereby cause an irreversible
loss of nuclear spin polarization. At the same time, quadrupolar interactions
lead to a complete suppression of angular momentum exchange between the nuclear
spin ensemble and its environment, resulting in nuclear spin relaxation times
on the order of hours.
},
added-at = {2009-05-14T09:20:20.000+0200},
author = {Maletinsky, P. and Kroner, M. and Imamoglu, A.},
biburl = {https://www.bibsonomy.org/bibtex/2f230cf1d03c7b7efa8f01124cb25a65b/ggiedke},
description = {Demagnetization of Quantum Dot Nuclear Spins: Breakdown of the Nuclear
Spin Temperature Approach},
interhash = {663ee48bf1038c774adffddfe48afbf7},
intrahash = {f230cf1d03c7b7efa8f01124cb25a65b},
keywords = {dot experiment hyperfine nuclear quantum spins},
note = {cite arxiv:0901.2289
Comment: 6 pages, 3 figures},
timestamp = {2009-05-14T09:20:20.000+0200},
title = {Demagnetization of Quantum Dot Nuclear Spins: Breakdown of the Nuclear
Spin Temperature Approach},
url = {http://arxiv.org/abs/0901.2289},
year = 2009
}