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The spin-Peierls instability in spin 1/2 XY chain in the non adiabatic limit

Shreekantha Sil
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Abstract

The spin-Peierls instability in spin 1/2 XY chain coupled to dispersionless phonons of frequency $ω$ has been studied in the nonadiabatic limit. We have chosen the Lang-Firsov variational wave function for the phonon subsystem to obtain an effective spin Hamiltonian. The effective spin Hamiltonian is then solved in the framework of mean-field approximation. We observed a dimerized phase when g is less than a critical value and an anti-ferromagnetic phase when it is greater than a critical value . The variation of lattice distortion, dimerized order parameter and energy gap with spin phonon coupling parameter has also been investigated here.

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Shreekantha Sil. 1998-03-31. The spin-Peierls instability in spin 1/2 XY chain in the non adiabatic limit. https://doi.org/10.1088/0953-8984%2F10%2F39%2F020

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