Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 45: Correlated Electrons: Poster Session

TT 45.104: Poster

Donnerstag, 29. März 2012, 15:00–19:00, Poster B

Collective Excitations of Quantum Solid Phases — •Guenther Meissner and Uwe Schmitt — Department of Physics, Saarland University, P.O.B. 151150, D-66041 Saarbruecken, Germany

For collective excitations of quantum solid phases at low temperatures as, e.g., sound propagation in solid helium or in magnetic field-induced 2D Wigner solids, Born’s classical theory of lattice dynamics breaks down. This happens due to large zero-point motions of the helium atoms with low mass and the cyclotron motions of the electrons with electrical charge. These deficiencies have been removed in our general quantum many-body approach, where the collective excitations are obtained quite generally from correlation functions allowing, e.g., also to include the balance between single-particle and collective excitations [1]. In the presence of random disorder the dispersion of the modes of these collective excitations is no longer gapless in zero wave vector limit. The gap has been considered in recent microwave resonance experiments being a confirmation of a disorder-pinned 2D Wigner quantum solid phase [2]. It will be shown, that from a theoretical point of view this interpretation in terms of quasi-particles of magnetic flux quanta and fractional charge is feasible, particularly, since the resonances observed near the fractional filling factor one third are very similar to those, found near the integer filling factor one.
G. Meissner, Phys. Rev. Lett. 21, 435 (1968); Physica B 184, 66 (1993).
Hahn Zhu, Yong P. Chen, P. Jiang, L.W. Engel, D.C. Tsui, L.N. Pfeiffer and K.W. West, Phys. Rev. Lett. 105, 126803 (2010) and references therein.