%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 }