排序方式: 共有11条查询结果,搜索用时 750 毫秒
1.
Irene Dujovne C.F. Hirjibehedin A. Pinczuk Moonsoo KangB.S. Dennis L.N. PfeifferK.W. West 《Solid State Communications》2003,127(2):109-115
Resonant inelastic light scattering experiments access the low lying excitations of electron liquids in the fractional quantum Hall regime in the range 2/5≥ν≥1/3. Modes associated with changes in the charge and spin degrees of freedom are measured. Spectra of spin reversed excitations at filling factor ν?1/3 and at ν?2/5 identify a structure of lowest spin-split Landau levels of composite fermions (CFs) that is similar to that of electrons. Observations of spin wave excitations enable determinations of energies required to reverse spin. The spin reversal energies obtained from the spectra illustrate the significant residual interactions of composite fermions. At ν=1/3 energies of spin reversal modes are larger but relatively close to spin conserving excitations that are linked to activated transport. Predictions of composite fermion theory are in good quantitative agreement with experimental results. 相似文献
2.
Gallais Y Kirschenmann TH Dujovne I Hirjibehedin CF Pinczuk A Dennis BS Pfeiffer LN West KW 《Physical review letters》2006,97(3):036804
Spin excitations from a partially populated composite fermion level are studied above and below nu=1/3. In the range 2/7相似文献
3.
Groshaus JG Dujovne I Gallais Y Hirjibehedin CF Pinczuk A Tan YW Stormer H Dennis BS Pfeiffer LN West KW 《Physical review letters》2008,100(4):046804
Neutral spin texture (ST) excitations at nu=1/3 are directly observed for the first time by resonant inelastic light scattering. They are determined to involve two simultaneous spin flips. At low magnetic fields, the ST energy is below that of the magnetoroton minimum. With increasing in-plane magnetic field these mode energies cross at a critical ratio of the Zeeman and Coulomb energies of eta(c)=0.020+/-0.001. Surprisingly, the intensity of the ST mode grows with temperature in the range in which the magnetoroton modes collapse. The temperature dependence is interpreted in terms of a competition between coexisting phases supporting different excitations. We consider the role of the ST excitations in activated transport at nu=1/3. 相似文献
4.
Rhone TD Majumder D Dennis BS Hirjibehedin C Dujovne I Groshaus JG Gallais Y Jain JK Mandal SS Pinczuk A Pfeiffer L West K 《Physical review letters》2011,106(9):096803
Even though composite fermions in the fractional quantum Hall liquid are well established, it is not yet known up to what energies they remain intact. We probe the high-energy spectrum of the 1/3 liquid directly by resonant inelastic light scattering, and report the observation of a large number of new collective modes. Supported by our theoretical calculations, we associate these with transitions across two or more composite fermions levels. The formation of quasiparticle levels up to high energies is direct evidence for the robustness of topological order in the fractional quantum Hall effect. 相似文献
5.
Y. Gallais T.H. Kirschenmann C.F. Hirjibehedin I. Dujovne A. Pinczuk L.N. Pfeiffer K.W. West 《Physica E: Low-dimensional Systems and Nanostructures》2006,34(1-2):144
We report inelastic light scattering experiments in the fractional quantum Hall regime at filling factors . A spin mode is observed below the Zeeman energy. The filling factor dependence of the mode energy is consistent with its assignment to spin flip excitations of composite fermions (CF) with four attached flux quanta (φ=4). Our findings reveal a CF Landau level structure in the φ=4 sequence. 相似文献
6.
New low-lying excitations are observed by inelastic light scattering at filling factors nu=p/(phip+/-1) of the fractional quantum Hall regime with phi=4. Coexisting with these modes throughout the range nu < or =1/3 are phi=2 excitations seen at 1/3. Both phi=2 and phi=4 excitations have distinct behaviors with temperature and filling factor. The abrupt first appearance of the new modes in the low-energy excitation spectrum at nu > or near 1/3 suggests a marked change in the quantum ground state on crossing the phi=2-->phi=4 boundary at nu=1/3. 相似文献
7.
C.F. Hirjibehedin Irene Dujovne I. Bar-JosephA. Pinczuk B.S. DennisL.N. Pfeiffer K.W. West 《Solid State Communications》2003,127(12):799-803
Strong resonant enhancements of inelastic light scattering from the long wavelength inter-Landau level magnetoplasmon and the intra-Landau level spin wave excitations are seen for the fractional quantum Hall state at ν=1/3. The energies of the sharp peaks (FWHM 0.2 meV) in the profiles of resonant enhancement of inelastic light scattering intensities coincide with the energies of photoluminescence bands assigned to negatively charged exciton recombination. To interpret the observed enhancement profiles, we propose three-step light scattering mechanisms in which the intermediate resonant transitions are to states with charged excitonic excitations. 相似文献
8.
In this paper a proof of existence and non-existence of theconically self-similar free-vortex solutions to the Navier-Stokesequations, originally found by Yih et al. (1982, Phys. Fluids.25, 2147-2158), is presented. This proof clearly establishesthat these solutions do not have any kind of singularity atthe symmetry axis. This analysis gives considerably improvedexistence and non-existence bounds and it is shown that thesebounds are close to optimal in the low-swirling limit. Thisapproach links the questions of existence and non-existencefor the swirling case and for the non-swirling case. The proof,which is an extension of techniques developed by Serrin (1972,Phil. Trans. R. Soc. Lond. 271, 325-360), is based on Schauder'sFixed Point Theorem and is, therefore, non-constructive. Therefore,the paper ends with a brief discussion of the question of howto compute the conically self-similar free-vortex solutionsto the Navier-Stokes equations. 相似文献
9.
M. A. Eriksson A. Pinczuk B. S. Dennis C. F. Hirjibehedin S. H. Simon L. N. Pfeiffer K. W. West 《Physica E: Low-dimensional Systems and Nanostructures》2000,6(1-4)
We report the observation of sharp plasmon and magnetoplasmon modes in ultra-low-density 2D electron systems. Well defined dispersions for the modes are observed at densities as low as 1.1×109 cm−2 and with excitation wave vectors as large as 1.2×105 cm−1. Interestingly, both modes are found to be more easily measured in low-density systems than in high-density systems. The strength of the light scattering cross-sections at low density suggests potential applications to the study of quantum phase transitions at large rs. 相似文献
10.
Hirjibehedin CF Dujovne I Pinczuk A Dennis BS Pfeiffer LN West KW 《Physical review letters》2005,95(6):066803
Resonant inelastic light scattering experiments at nu = 1/3 reveal a novel splitting of the long-wavelength modes in the low energy spectrum of quasi-particle excitations in the charge degree of freedom. We find a single peak at small wave vectors that splits into two distinct modes at larger wave vectors. The evidence of well-defined dispersive behavior at small wave vectors indicates a coherence of the quantum fluid in the micron length scale. We evaluate interpretations of long-wavelength modes of the electron liquid. 相似文献