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Register a new userResonant Enhancement of Inelastic Light Scattering in the Fractional Quantum Hall Regime at $ u=1/3$
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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 $ u = 1/3$. The energies of the sharp peaks (FWHM $lesssim 0.2meV$) 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.
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New low-lying excitations are observed by inelastic light scattering at filling factors $ u=p/(phi p pm 1)$ of the fractional quantum Hall regime with $phi=4$. Coexisting with these modes throughout the range $ u leq 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 $ u lesssim 1/3$ suggests a marked change in the quantum ground state on crossing the $phi=2 to phi=4$ boundary at $ u = 1/3$.
We report inelastic light scattering experiments in the fractional quantum Hall regime at filling factors $ ulesssim1/3$. A spin mode is observed below the Zeeman energy. The filling factor dependence of the mode energy is consistent with its assignment to spin flip excitations of composite fermions with four attached flux quanta ($phi$=4). Our findings reveal a composite fermion Landau level structure in the $phi$=4 sequence.
Resonant inelastic light scattering experiments at $ u=1/3$ reveal a novel splitting of the long wavelength modes in the low energy spectrum of quasiparticle excitations in the charge degree of freedom. We find a single peak at small wavevectors that splits into two distinct modes at larger wavevectors. The evidence of well-defined dispersive behavior at small wavevectors indicates a coherence of the quantum fluid in the micron length scale. We evaluate interpretations of long wavelength modes of the electron liquid.
Utilizing an electronic Fabry-Perot interferometer in which Coulomb charging effects are suppressed, we report experimental observation of anyonic braiding statistics for the $ u=1/3$ fractional quantum Hall state. Strong Aharonov-Bohm interference of the $ u=1/3$ edge mode is punctuated by discrete phase slips consistent with an anyonic phase of $theta_{anyon}=frac{2pi}{3}$. Our results are consistent with a recent theory of a Fabry-Perot interferometer operated in a regime in which device charging energy is small compared to the energy of formation of charged quasiparticles. Close correspondence between device operation and theoretical predictions substantiates our claim of observation of anyonic braiding.
Low lying excitations of electron liquids in the fractional quantum Hall (FQH) regime are studied by resonant inelastic light scattering methods. We present here results from charge and spin excitations of FQH states in the lowest spin-split Landau levels that are of current interest. In the range of filling factors $2/5 geq u geq 1/3$, we find evidence that low energy quasiparticle excitations can be interpreted with spin-split composite fermion quasi-Landau levels. At FQH states around $ u=3/2$, we find well-defined excitations at 4/3 and 8/5 that are consistent with a spin-unpolarized population of quasi-Landau levels.
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