Dresden 2014 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 18: Poster Session

MM 18.37: Poster

Montag, 31. März 2014, 18:00–20:00, P4

Electronic properties of metallic gallium up to 4 GPa as studied with new anvil-cell NMR — •Thomas Meier and Jürgen Haase — Universität Leipzig, Institut für Experimentelle Physik II

A new approach to nuclear magnetic resonance under pressures of several GPa is developed and is used to investigate the response of the electronic states, as well as the atomic motion in gallium (Ga) metal. Liquid Ga (below 2 Gpa) was studied, as well as solid Ga in the cubic Ga-II phase at pressures up to 4 GPa. We found distinct deviations from what is expected for a free electron liquid, which cannot be explained with current theories. The change in the electronic properties upon the pressure inducing solidification at 2 GPa, indicates a dramatic change in the electronic density of states at the Fermi level, which is a characteristic feature of anomalous melting metals. The investigation of the nuclear spin-lattice relaxation allows us also to determine the correlation time of the fluctuations of the electric field gradient at the nuclei produced by the high atomic mobility in the melt. We find the correlation time to increase linearly with pressure, up to the phase transition. Additionally, the observed freezing and melting behaviour of liquid gallium/gallium I at various pressures displayed a distinct hysteresis, indicating pressure induced alterations in the crystallisation behaviour of volume constricted gallium metal.