Zobrazeno 1 - 10
of 404
pro vyhledávání: '"Vakili, K."'
Autor:
Schmitt, E., Vakili, K.
Principal component analysis (PCA) is widely used to analyze high-dimensional data, but it is very sensitive to outliers. Robust PCA methods seek fits that are unaffected by the outliers and can therefore be trusted to reveal them. FastHCS (High-dime
Externí odkaz:
http://arxiv.org/abs/1402.3514
Publikováno v:
Phys. Rev. B. 79, 195311 (2009)
We measure the effective mass (m*) of interacting two-dimensional electrons confined to a 4.5 nm-wide AlAs quantum well. The electrons in this well occupy a single out-of-plane conduction band valley with an isotropic in-plane Fermi contour. When the
Externí odkaz:
http://arxiv.org/abs/0905.0658
Autor:
Gokmen, T., Padmanabhan, Medini, Gunawan, O., Shkolnikov, Y. P., Vakili, K., De Poortere, E. P., Shayegan, M.
Publikováno v:
Phys. Rev. B 78, 233306 (2008)
We demonstrate that, in a quasi-two-dimensional electron system confined to an AlAs quantum well and occupying two conduction-band minima (valleys), a parallel magnetic field can couple to the electrons' orbital motion and tune the energies of the tw
Externí odkaz:
http://arxiv.org/abs/0811.3194
Autor:
Bishop, N. C., Padmanabhan, M., Vakili, K., Shkolnikov, Y. P., De Poortere, E. P., Shayegan, M.
We report magnetotransport measurements of fractional quantum Hall states in an AlAs quantum well around Landau level filling factor nu = 3/2, demonstrating that the quasiparticles are composite Fermions (CFs) with a valley degree of freedom. By moni
Externí odkaz:
http://arxiv.org/abs/0706.1195
Publikováno v:
Nature Physics 3, 388 - 391 (2007)
Using symmetry breaking strain to tune the valley occupation of a two-dimensional (2D) electron system in an AlAs quantum well, together with an applied in-plane magnetic field to tune the spin polarization, we independently control the system's vall
Externí odkaz:
http://arxiv.org/abs/cond-mat/0609493
Two-dimensional electrons in AlAs quantum wells occupy multiple conduction-band minima at the X- points of the Brillouin zone. These valleys have large effective mass and g-factor compared to the stan-dard GaAs electrons, and are also highly anisotro
Externí odkaz:
http://arxiv.org/abs/cond-mat/0606158
Publikováno v:
Solid State Comm. 140, 285 (2006)
We have realized an AlAs two-dimensional electron system in which electrons occupy conduction-band valleys with different Fermi contours and effective masses. In the quantum Hall regime, we observe both resistivity spikes and persistent gaps at cross
Externí odkaz:
http://arxiv.org/abs/cond-mat/0606120
Publikováno v:
Phys. Rev. Lett. 97, 116803 (2006)
We report measurements of the quantum Hall state energy gap at avoided crossings between Landau levels originating from different conduction band valleys in AlAs quantum wells. These gaps exhibit an approximately linear dependence on magnetic field o
Externí odkaz:
http://arxiv.org/abs/cond-mat/0606072
Publikováno v:
Appl. Phys. Lett. 89, 172118 (2006).
Employing state-of-the-art molecular beam epitaxy techniques to grow thin, modulation-doped AlAs quantum wells, we have achieved a low temperature mobility of 5.5 m$^2$/Vs with out-of-plane occupation, an order of magnitude improvement over previous
Externí odkaz:
http://arxiv.org/abs/cond-mat/0606071
Publikováno v:
Phys. Rev. Lett. 97, 186 404 (2006).
We report direct measurements of the valley susceptibility, the change of valley population in response to applied symmetry-breaking strain, in an AlAs two-dimensional electron system. As the two-dimensional density is reduced, the valley susceptibil
Externí odkaz:
http://arxiv.org/abs/cond-mat/0605692