Dresden 2009 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 48: Poster 2
HL 48.6: Poster
Thursday, March 26, 2009, 15:00–17:30, P2
OEP-DFT computation of spin current densities and Wigner transition in a one-dimensional ring — •Thorsten Arnold, Marc Siegmund, and Oleg Pankratov — Lehrstuhl für Theoretische Festkörperphysik - Institut für Theoretische Physik IV - Staudtstr. 7-B2 - 91058 Erlangen
We investigate by exchange-only DFT, using the OEP-method in the KLI-approximation, a quasi one-dimensional Wigner crystallisation transition. We consider interacting electrons on a ring, assuming a Fermi liquid behaviour of the electron system. The transition from a gas-like to a pinned (by an impurity potential) crystal state can be identified totally within DFT, i.e. using collective variables (density and current) only, and not employing the correlation function. This is achieved by calculating a persistent current in magnetic field. Varying the electron-electron interaction strength in terms of parameter rs, we found that the current decays exponentially for rs>rsc. In a case of spinless electrons, we found a critical value of rsc=2.05 (for 10 electrons). [1]
In this work, the model is extended for particles with spin. Fixing the total spin moment, we found both spin subsystems undergoing the Wigner transition successively at rsc of the order of 0.1. The ground state magnetisation for 10 electrons rises from S=0 for rs<0.1 (gas state) to S=1 (0.1<rs<0.2) in a crystalline state.
[1] M. Siegmund, M. Hofmann, and O. Pankratov, arXiv:0711.2937v1