Berlin 2008 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 17: Poster I

DY 17.10: Poster

Tuesday, February 26, 2008, 16:00–18:00, Poster C

Mesoscopic Coulomb Supersolid — Alexei Filinov¹, •Jens Böning¹, Michael Bonitz¹, and Yurii Lozovik² — ¹Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität, Kiel, Germany — ²Institute of Spectroscopy of the Russian Academy of Sciences, Troitsk, Russia

When a few tens of charged particles are trapped in a spherical electrostatic potential at low temperature they form concentric shells resembling atoms. These “artificial atoms” can be easily controlled by varying the confinement strength. We analyze such systems for the case that the particles are bosons and find superfluid behavior which even persists in the solid state. We show that while in the liquid phase the superfluid fractions on different shells are similar, in the radially ordered, but orientationally disordered state, the shells contribute very differently. For clusters with hexagonal symmetry which have the highest stability against intershell rotation, the superfluid fraction in the core region is reduced and superfluidity may persist only at the boundary, as known from, e.g., crystal grains [1] and parahydrogen clusters [2]. In contrast, pronounced concentration of superfluidity in the cluster core is observed for N=21−23, 30−32, and N = 39−42. This novel state of matter is a mesoscopic supersolid [3].

[1] S. Sasaki et al., Science 313, 1098 (2006)

[2] S. A. Khairallah et al., Phys. Rev. Lett. 98, 183401 (2007)

[3] A. Filinov, J. Böning, M. Bonitz and Yu E. Lozovik, arXiv:0711.1255