6 papers
Ultra-high magnetic field study of the layer split bands in Graphite
R. J. Nicholas, P. Y. Solane, O. Portugall
We report studies of the magnetospectroscopy of graphite into a new regime of high energies and ultra-high magnetic fields which allows us to perform the first spectroscopic studie…
The origin of electron-hole asymmetry in graphite
P. Plochocka, P. Y. Solane, R. J. Nicholas +5
The electron hole asymmetry has been measured in natural graphite using magneto-optical absorption measurements. A splitting is observed for the transitions at both the -point a…
Measurements of the Composite Fermion masses from the spin polarization of 2-D electrons in the region
R. Chughtai, V. Zhitomirsky, R. J. Nicholas +1
Measurements of the reflectivity of a 2-D electron gas are used to deduce the polarization of the Composite Fermion hole system formed for Landau level occupancies in the regime 1<…
Free carrier effects in gallium nitride epilayers: the valence band dispersion
P. A. Shields, R. J. Nicholas, F. M. Peeters +2
The dispersion of the A-valence-band in GaN has been deduced from the observation of high-index magneto-excitonic states in polarised interband magneto-reflectivity and is found to…
Critical Collapse of the Exchange Enhanced Spin Splitting in 2-D Systems
D. R. Leadley, R. J. Nicholas, J. J. Harris +1
The critical filling factor v_c where Shubnikov-de Haas oscillations become spin split is investigated for a set of GaAs-GaAlAs heterojunctions. Finite temperature magnetoresistanc…
Pulsed Magnetic Field Measurements of the Composite Fermion Effective Mass
D. R. Leadley, M. van der Burgt, R. J. Nicholas +2
Magnetotransport measurements of Composite Fermions (CF) are reported in 50 T pulsed magnetic fields. The CF effective mass is found to increase approximately linearly with the eff…