Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 61: Poster II: Materials, Interfaces and Heterostructures
HL 61.3: Poster
Donnerstag, 25. März 2010, 18:00–20:00, Poster D1
Neutron Scattering and ab initio Studies of CuCrS2 — •Karin Schmalzl1, Julia Rasch2,3, Martin Boehm2, Hannu Mutka2, Juerg Schefer3, G. M. Abramova4, and Joerg F. Loeffler5 — 1IFF, Forschungszentrum Juelich, JCNS at ILL, 38042 Grenoble, France — 2Institut Laue-Langevin, BP 156, 38042 Grenoble, France — 3LNS, ETH Zuerich and PSI, 5232 Villigen PSI, Switzerland — 4L. V. Kirensky Institute of Physics, SB RAS, Krasnoyarsk, 660036, Russia — 5Laboratory of Metal Physics and Technology, Department of Materials, ETH Zuerich, 8093 Zuerich, Switzerland
Transition metal dichalcogenides show a quasi-two dimensional layered structure leading to interesting electronic properties like charge density wave or superconductivity. Due to the triangular lattice of the Cr3+ ions CuCrS2 is prone to geometrical frustration. Below TN=37 K a complex magnetic structure with an incommensurable magnetic propagation vector is present. The magnetic order is coupled to a structural transition. At higher temperatures ionic conductivity of the weakly bound Cu ions emerges.
Inelastic neutron scattering experiments below TN show a strong non-dispersive, localised mode in Q at about 12 meV. Additionally an enhanced intensity has been observed at crossings of phonon and magnon modes at about 8 meV. Temperature dependent measurements of the phonon density of states show a change of low lying phonon branches, where the strongest change appears at about 150 K at an energy of about 8 meV. Ab initio calculations assign this energy to in plane motions of the Cu atoms.