Ground state properties of the bond alternating spin-1/2 anisotropic Heisenberg chain

Ground state properties, dispersion relations and scaling behaviour of spin gap of a bond alternating spin- 1/2 anisotropic Heisenberg chain have been studied where the exchange interactions on alternate bonds are ferromagnetic (FM) and antiferromagnetic (AFM) in two separate cases. The resulting m...

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Bibliographic Details
Date:2017
Main Authors: Paul, S., Ghosh, A.K.
Format: Article
Language:English
Published: Інститут фізики конденсованих систем НАН України 2017
Series:Condensed Matter Physics
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/156996
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:Ground state properties of the bond alternating spin-1/2 anisotropic Heisenberg chain / S. Paul, A.K. Ghosh // Condensed Matter Physics. — 2017. — Т. 20, № 2. — С. 23701: 1–16 . — Бібліогр.: 36 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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Summary:Ground state properties, dispersion relations and scaling behaviour of spin gap of a bond alternating spin- 1/2 anisotropic Heisenberg chain have been studied where the exchange interactions on alternate bonds are ferromagnetic (FM) and antiferromagnetic (AFM) in two separate cases. The resulting models separately represent nearest neighbour (NN) AFM-AFM and AFM-FM bond alternating chains. Ground state energy has been estimated analytically by using both bond operator and Jordan-Wigner representations and numerically by using exact diagonalization. Dispersion relations, spin gap and several ground state orders have been obtained. Dimer order and string orders are found to coexist in the ground state. Spin gap is found to develop as soon as the non-uniformity in alternating bond strength is introduced in the AFM-AFM chain which further remains non-zero for the AFM-FM chain. This spin gap along with the string orders attribute to the Haldane phase. The Haldane phase is found to exist in most of the anisotropic region similar to the isotropic point. Key words: bond alternating, spin gap, bond operator, string orders, dimer order, scali