Zobrazeno 1 - 10
of 52
pro vyhledávání: '"Lumpkin, N."'
Publikováno v:
J. Phys.: Condens. Matter 20, 415226 (2008)
We observe a complex change in the hopping exponent value from 1/2 to 1/3 as a function of disorder strength and electron density in a sodium-doped silicon MOSFET. The disorder was varied by applying a gate voltage and thermally drifting the ions to
Externí odkaz:
http://arxiv.org/abs/0705.4241
Publikováno v:
Physica B 400, 218 (2007)
Sodium impurities are diffused electrically to the oxide-semiconductor interface of a silicon MOSFET to create an impurity band. At low temperature and at low electron density, the band is split into an upper and a lower sections under the influence
Externí odkaz:
http://arxiv.org/abs/cond-mat/0512124
Publikováno v:
J. Phys.: Condens. Matter 19, 226216 (2007)
We have studied the temperature dependence of the conductivity of a silicon MOSFET containing sodium ions in the oxide above 20 K. We find the impurity band resulting from the presence of charges at the silicon-oxide interface is split into a lower a
Externí odkaz:
http://arxiv.org/abs/cond-mat/0512039
Publikováno v:
Phys. Rev. B 73, 4, 041304 (2006)
We report measurements of the temperature-dependent conductivity in a silicon metal-oxide-semiconductor field-effect transistor that contains sodium impurities in the oxide layer. We explain the variation of conductivity in terms of Coulomb interacti
Externí odkaz:
http://arxiv.org/abs/cond-mat/0510145
Autor:
O'Brien, J. L., Hamilton, A. R., Clark, R. G., Mielke, C. H., Smith, J. L., Cooley, J. C., Rickel, D. G., Starrett, R. P., Reilly, D. J., Lumpkin, N. E., Hanrahan, Jr., R. J., Hults, W. L.
Publikováno v:
Phys. Rev. B 66, 064523 (2002)
We report complex ac magnetic susceptibility measurements of a superconducting transition in very high-quality single-crystal alpha-uranium using microfabricated coplanar magnetometers. We identify an onset of superconductivity at T~0.7 K in both the
Externí odkaz:
http://arxiv.org/abs/cond-mat/0208501
Autor:
Buehler, T. M., McKinnon, R. P., Lumpkin, N. E., Brenner, R., Reilly, D. J., Macks, L. D., Hamilton, A. R., Dzurak, A. S., Clark, R. G.
We describe a fabrication process for devices with few quantum bits (qubits), which are suitable for proof-of-principle demonstrations of silicon-based quantum computation. The devices follow the Kane proposal to use the nuclear spins of 31P donors i
Externí odkaz:
http://arxiv.org/abs/cond-mat/0208374
Autor:
Yasin, C. E., Simmons, M. Y., Hamilton, A. R., Lumpkin, N. E., Clark, R. G., Pfeiffer, L. N., West, K. W.
We investigate the relationship between the quantum Hall extended states and the apparent B=0 `metal'-insulator transition in extremely low density, high quality two-dimensional n-GaAs systems (\mu_{peak} ~ 2 x 10^7 cm^2/Vs). The combination of small
Externí odkaz:
http://arxiv.org/abs/cond-mat/0204519
Autor:
Reilly, D. J., Facer, G. R., Dzurak, A. S., Kane, B. E., Clark, R. G., Stiles, P. J., O'Brien, J. L., Lumpkin, N. E., Pfeiffer, L. N., West, K. W.
Publikováno v:
Phys. Rev. B 63, 121311(R) (2001)
Zero length quantum wires (or point contacts) exhibit unexplained conductance structure close to 0.7 X 2e^2/h in the absence of an applied magnetic field. We have studied the density- and temperature-dependent conductance of ultra-low-disorder GaAs/A
Externí odkaz:
http://arxiv.org/abs/cond-mat/0001174
Autor:
O'Brien, J. L., Nakagawa, H., Dzurak, A. S., Clark, R. G., Kane, B. E., Lumpkin, N. E., Miura, N., Mitchell, E. E., Goettee, J. D., Brooks, J. S., Rickel, D. G., Starrett, R. P.
Publikováno v:
Phys. Rev. B 61, 1584 (2000)
The B-T phase diagram for thin film YBa_2Cu_3O_7-d with B parallel to the superconducting layers has been constructed from GHz transport measurements to 150T. Evidence for a transition from a high T regime dominated by orbital effects, to a low T reg
Externí odkaz:
http://arxiv.org/abs/cond-mat/9901341
Autor:
Facer, G. R., Kane, B. E., Dzurak, A. S., Heron, R. J., Lumpkin, N. E., Clark, R. G., Pfeiffer, L. N., West, K. W.
We report measurements of GaAs/AlGaAs undoped field-effect transistors in which two-dimensional electron gases (2DEGs) of exceptional quality and versatility are induced without modulation doping. Electron mobilities at T=4.2 K and density 3 E11 /cm^
Externí odkaz:
http://arxiv.org/abs/cond-mat/9805197