Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 33: Postersession Correlated Electrons: Metal Insulator Transition, Spin Systems and Itinerant Magnets
TT 33.7: Poster
Mittwoch, 25. März 2009, 14:00–18:00, P1A
Prediction of insulator to metal transition in rubidium sesquioxide (Rb4O6) under high pressure — •S. Shahabeddin Naghavi1, Gerhard H. Fecher1, Claudia Felser1, Jürgen Kübler2, and Klaus Doll3 — 1Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, 55099 Mainz — 2Institut für Festkörperphysik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany — 3Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart
We report on theoretical predictions of the insulator-metal transition in rubidium sesquioxide (Rb4O6) under high pressure implemented by crystal06 code. Two types of oxygen molecules exist in the sesquioxide Rb4O6; these are the paramagnetic hyperoxide O2− (two times) and the peroxide O2– (one molecule). By choosing the ferromagnetic solution and distinguishing between the two different kinds of oxygen molecules, the symmetry is reduced from cubic structure with the symmetry I43d to tetragonal (I42d ). By increasing the pressure, the differences in the bond-lengths between paramagnetic hyperoxide and peroxide is reduced until finally at a pressure of 162 Gpa they become the same. Moreover, at this pressure, the insulating state becomes metallic and the magnetism disappears. Independent calculations indicate that the equalization of the bond-lengths is essential for loosing the magnetic properties.