Neel to spin-Peierls transition in the ground and excited state of a quasi-1D Heisenberg model coupled to bond phonons.

The spin-Peierls transtion in the ground state (quantum phase transition) and excited state(thermal phase transition) of a quasi-1D Heisenberg model is investigated using the stochastic series expansion quantum monte carlo method. The transition from a gapless Neel state to a spin-gapped Peierls sta...

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Bibliographic Details
Main Author: Pillay, Jason Cornelius.
Other Authors: School of Physical and Mathematical Sciences
Format: Final Year Project
Language:English
Published: 2012
Subjects:
Online Access:http://hdl.handle.net/10356/49063
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Institution: Nanyang Technological University
Language: English
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Summary:The spin-Peierls transtion in the ground state (quantum phase transition) and excited state(thermal phase transition) of a quasi-1D Heisenberg model is investigated using the stochastic series expansion quantum monte carlo method. The transition from a gapless Neel state to a spin-gapped Peierls state is studied in the parameter space spanned by spatial anisotropy, inter-chain coupling and spin-lattice coupling. It is found that for any inter-chain coupling, the transition to a dimerized Peierls state only occurs when the spin-lattice coupling exceeds a finite, non-zero critical value.