Effect of structural disorder on quantum oscillations in graphite

Abstract

Electrical and structural characterization of a single Ga Sb ∕ In As ∕ Ga Sb quantum well grown on GaAs using interface misfit dislocations J. Appl. Phys. 104, 074901 (2008); 10.1063/1.2982277Influence of the hybridization of impurity electron states on the quantum magneto-oscillation phenomena in mercury selenide with iron impurities Low Temp.

Macroscopic-ranged proximity effect in graphite

“…Pristine samples, however, showed no superconducting-like transitions, consistently with most reports on the literature to date [11,21,17,38,39]. Such observation requires that the transfer of charge from bulk graphite to the hypothesized superconducting regions must be forbidden under normal conditions.…”

“…The increase of I s with B for B < 0.1 T can be understood qualitatively by the circuit shown in Fig. 3, assuming the low resistive channel R s ≪ R independent of B in this field range and that I s is limited by some interface resistance r. In this case ∆R 4p /R 4p (T > T c ) ≈ 3R/(3R + 2r), which describes well the experimental data, with R ∝ B 1.2 the typical magnetoresistance of graphite and r constant [11]. Although the amplitude of the 4p anomaly did not change monotonically with T, the temperature in which it occurred was displaced by the presence of magnetic fields according to the empirical expression…”

“…Suitably, the occurrence of the conventional superconducting PE does not seem to justify the 4p transition either. As discussed previously, the lack of features in samples with a single SC electrode, the null dependence on T, the increasing transition amplitude with magnetic fields and the long range of the phenomenon (up to 700 µm -1 mm distant from the superconducting electrodes, whereas ξ N ≈ 1−2 µm [1,9,10,11,32,33,34]) all attest against such hypothesis.…”

“…A promising candidate satisfying such conditions is graphite, which can be described as a quasicompensated layered semimetal. In this highly anisotropic material, ρ a /ρ c < 10 −4 , l 10 µm and v F ≈ 10 6 m/s [9,10,11]. These values lead to large estimated normal coherence lengths at low temperatures ξ N (T = 4 K) = v F /2πk B T ≈ 2 µm.…”

Crystallographically Textured Electrodes for Rechargeable Batteries: Symmetry, Fabrication, and Characterization

“…Moving on from this simplistic example, we now consider a fiber-textured sample. The shape of the peak detected in a rocking curve scan evaluates the strength of an out-of-plane fiber texture; a sharper peak, that is, a smaller full-width at half-maximum (FWHM) value, suggests that the crystallites orient the reciprocal lattice vector G hkl in question collectively upward with a narrower angular distribution . This technique has also been used to characterize the crystallinity and orientational order of layered materials before/after intercalation of guest ions (Figure A). , The graphite sample with the narrowest peak in the rocking curve scan exhibits the most pronounced quantum oscillation (Figure B), suggesting a high electronic quality.…”