Physical review. B, Condensed matter

Aharonov-Casher effect in the Heisenberg spin chain with many impurities

Andrei A. Zvyagin, P. Schlottmann

Published Sep 1, 1995• 48 citations

Abstract

The Aharonov-Casher effect is a quantum interference arising in mesoscopic rings involving particles with magnetic moments. The wave function acquires a phase due to an electric-field flux F enclosed by the ring and gives rise to flux-dependent oscillations in persistent spin currents. In the ground state of the spin-1/2 Heisenberg chain the period and amplitude of the oscillations are associated with the properties of the Fermi surface of the elementary excitations of the spin chain (spinons). We consider an antiferromagnetic spin-1/2 Heisenberg ring with a concentration x of impurity spins S. The calculations are performed within the framework of Bethe's ansatz. Due to the finite concentration of impurities the ground state consists of two (rather than one) Dirac seas, corresponding to spinons and 2S strings of rapidities. The persistent spin current reveals two periods of oscillation associated with the properties of the two Fermi seas. The interference pattern as a function of F is discussed for several external magnetic fields.

DOI: 10.1103/physrevb.52.6569

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