Muelleret al. reply

Abstract

Mueller et al. Reply: The Comment [1] by Mazin et al.interprets the de Haas-van Alphen (dHvA) measurements [2] of Fowler et al. making the interesting suggestion that the separation between the low 0.53 and 0.78 kT peaks in the power spectral density and also the barely resolved two higher peaks at 3.51 ±0.11 kT are due to the effect of spin splitting. They obtain good agreement with the extremal cross-sectional areas if they shift their chainlike band downward by about 60 meV.In presenting our analysis in Ref.[2] we had restricted [3] ourselves to three independent Lifshitz-Kosevich (LK) frequencies only. It is not clear to us whether the dHvA Y-Ba-Cu-O (YBCO) data were taken in a normal metallic, superconducting, or induced ferromagnetic region of the YBCO phase diagram [2]. Few experiments on cuprate superconductors have been carried out in 100-T fields. This question remains unresolved and is one on which several laboratories including ours are actively working.Here we adopt the point of view of Mazin et al. and have fitted the data of Ref.[2] using two base cross sections, each Zeeman split. Because we are close to the quantum limit (index «=1), dHvA oscillations are no longer exactly periodic in \/B (the cross section itself is a function of external B). This effect has been observed [4] in the needles of Zn. It means that each dHvA Landau frequency is split in the power spectral density into two "bumps" or peaks, in contrast to an interpretation based on strict adherence to LK theory which yields only a single peak.In Table I we list the power spectral density peak frequencies. A fitted recomparison with the Fowler et al. magnetization data similar to Fig. 1 of [2] suggests that the quality of fit using two spin-split frequencies was improved by about a factor of 3. Yu et al. can also [5] fit these results using their electronic band structure if they shift their bands by about 20 meV. TABLE I. YBCO frequencies F in kilotesla, quantum index (F/B) in 100-T field B, cyclotronic masses in electronic mass, and scattering Dingle temperatures in kelvin. F 0.53 ±0.02 0.78 ±0.02 3.41 ±0.10 3.62 ±0.10 Quantum index 5 7 33 37 Mass 7.0 ±2.5 7.2 ±2.5 7.3 ±2.6 7.5 ±2.7 Dingle temperature 1.7 ±0.6 2.1 ±0.7 3.3 ±1.2 3.5 ±1.3 Shift sign + -+ -It appears that spin-split cyclotron orbits offer a valid interpretation of the dHvA results of Fowler et al. in the 100-T regime. dHvA analysis in the quantum limit.[5] J.

Dark atoms with nuclear shell: A status review

“…Note that the migration rate considered here is larger than that observed at the Oklo site for heavy elements [79]. The upper limits on the anomalous helium abundance are very stringent [80] r oE ≤ 10 −19 , and our rough estimate is ten orders of magnitude too large. Together with the other problems of the OBe Universe stipulated above, this rules out the OBe scenario.…”

Diffractive J/Ψ production in high energy γγ collisions as a probe of the QCD pomeron

“…those where the magnitudes of the two hard scales are comparable. The two classical processes which can probe the QCD pomeron by fulfilling these criteria are deep inelastic events accompanied by an energetic (forward) jet [4,5]) and the production of large p T jets separated by the rapidity gap [6]. The former process probes the QCD pomeron in the forward direction while the latter reflects the elastic scattering of partons via the QCD pomeron exchange with non-zero (and large) momentum transfer.…”

New Photoluminescence Transition in GaAs InvolvingD−States

“…Further complications arise during the interpretation of QW FIR absorption spectra due to the possibility of confusing D 2 features with those arising from interexcited state neutral impurity transitions (from both well and barrier materials), as well as cyclotron resonance. Hence, identification of D 2 features in a given FIR absorption spectrum is not straightforward, relying on comparisons with quantitative theoretical predictions, and has often been controversial [1,[4][5][6][7]11].…”

“…The handful of studies [1-3] dealing with D 2 in bulk materials all involve significant binding energy enhancements due to magnetic fields. These early far infrared (FIR) investigations, albeit the first to identify D 2 states in bulk GaAs, suffered from a combination of materials and experimental technique-related problems which strictly limited these studies to the observation of relatively broad D 2 bands in a restricted number of compensated samples.As a result of these difficulties, recent effort has been focused on the study of 2D D 2 states in QW geometries, which also offer the possibility of engineering appropriate conditions for the creation of D 2 centers, via selective doping techniques [4][5][6][7]. While this has allowed D 2 centers to be identified in a less restricted variety of materials, the linewidths associated with the D 2 transitions observed in all of the existing FIR studies are still very broad, especially in comparison to the very small binding energy expected for D 2 in bulk GaAs [ϳ3.7 K or 2.6 cm 21 , where the effective Rydberg for neutral donors in GaAs is taken to be R ‫ء‬ 46.09 cm 21 (5.715 meV) [8] ] [9,10].…”

“…As a result of these difficulties, recent effort has been focused on the study of 2D D 2 states in QW geometries, which also offer the possibility of engineering appropriate conditions for the creation of D 2 centers, via selective doping techniques [4][5][6][7]. While this has allowed D 2 centers to be identified in a less restricted variety of materials, the linewidths associated with the D 2 transitions observed in all of the existing FIR studies are still very broad, especially in comparison to the very small binding energy expected for D 2 in bulk GaAs [ϳ3.7 K or 2.6 cm 21 , where the effective Rydberg for neutral donors in GaAs is taken to be R ‫ء‬ 46.09 cm 21 (5.715 meV) [8] ] [9,10].…”