Zobrazeno 1 - 10
of 35
pro vyhledávání: '"Dementyev, A. E."'
An equilibrium multielectron bubble in liquid helium is a fascinating object with a spherical two-dimensional electron gas on its surface. We describe two ways of creating them. MEBs have been observed in the dome of a cylindrical cell with an unexpe
Externí odkaz:
http://arxiv.org/abs/0910.3224
Publikováno v:
J. Chem. Phys, vol. 134, 154511 (2011)
Single crystal silicon is an excellent system in which to explore dynamic nuclear polarization (DNP), as it exhibits a continuum of properties from metallic to insulating as a function of doping concentration and temperature. At low doping concentrat
Externí odkaz:
http://arxiv.org/abs/0903.4699
We study two techniques to create electrons in a liquid helium environment. One is thermionic emission of tungsten filaments in a low temperature cell in the vapor phase with a superfluid helium film covering all surfaces; the other is operating a gl
Externí odkaz:
http://arxiv.org/abs/0811.0334
Publikováno v:
Phys. Rev. Lett. 100, 127601 (2008)
We report record high Si-29 spin polarization obtained using dynamic nuclear polarization in microcrystalline silicon powder. Unpaired electrons in this silicon powder are due to dangling bonds in the amorphous region of this intrinsically heterogene
Externí odkaz:
http://arxiv.org/abs/0711.4076
Publikováno v:
Phys. Rev. B, 77 024413 (2008)
In a dynamic nuclear polarization experiment on a 40 mM solution of 4-amino-TEMPO in a 40:60 water/glycerol mixture, we have observed that the bulk dipolar reservoir is cooled to a spin temperature of 15.5 micro-K, following microwave irradiation for
Externí odkaz:
http://arxiv.org/abs/0705.4671
Publikováno v:
Phys. Rev. Lett. 98, 190401 (2007)
NMR spin echo measurements of C-13 in C60, Y-89 in Y2O3, and Si-29 in silicon are shown to defy conventional expectations when more that one pi pulse is used. Multiple pi-pulse echo trains may either freeze our or accelerate the decay of the signal,
Externí odkaz:
http://arxiv.org/abs/0705.0667
Autor:
Li, Dale, Dong, Yanqun, Ramos, R. G., Murray, J. D., MacLean, K., Dementyev, A. E., Barrett, S. E.
In spectroscopy, it is conventional to treat pulses much stronger than the linewidth as delta-functions. In NMR, this assumption leads to the prediction that pi pulses do not refocus the dipolar coupling. However, NMR spin echo measurements in dipola
Externí odkaz:
http://arxiv.org/abs/0704.3620
NMR spin echo measurements of $^{29}$Si in Silicon powders have uncovered a variety of surprising phenomena that appear to be independent of doping. These surprises include long tails and even-odd asymmetry in Carr-Purcell-Meiboom-Gill (CPMG) echo tr
Externí odkaz:
http://arxiv.org/abs/cond-mat/0308584
Publikováno v:
Phys. Rev. Lett. 86, 5353 (2001)
Optically pumped nuclear magnetic resonance measurements of Ga-71 spectra were carried out in an n-doped GaAs/Al0.1Ga0.9As multiple quantum well sample near the integer quantum Hall ground state Nu=1. As the temperature is lowered (down to T~0.3 K),
Externí odkaz:
http://arxiv.org/abs/cond-mat/0009134
The Knight shift and the nuclear spin-lattice relaxation rate 1/T1 of Ga-71 nuclei are measured in GaAs quantum wells at Landau level filling factor nu = 1/2 using optically pumped NMR. The temperature dependences of these data are compared with pred
Externí odkaz:
http://arxiv.org/abs/cond-mat/9907280