Eur. Phys. J. B (2017) 90: 123
https://doi.org/10.1140/epjb/e2017-70693-7

Regular Article

Quantum to classical transition in the ground state of a spin-S quantum antiferromagnet

¹ The Institute of Mathematical Sciences, CIT Campus, Chennai 600113, India
² School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India

^a e-mail: bimladanu@imsc.res.in

Received: 20 November 2016
Received in final form: 20 March 2017
Published online: 26 June 2017

Abstract

We study a frustrated spin-S staggered-dimer Heisenberg model on square lattice by using the bond-operator representation for quantum spins, and investigate the emergence of classical magnetic order from the quantum mechanical (staggered-dimer singlet) ground state for increasing S. Using triplon analysis, we find the critical couplings for this quantum phase transition to scale as 1 /S(S + 1). We extend the triplon analysis to include the effect of quintet dimer-states, which proves to be essential for establishing the classical order (Néel or collinear in the present study) for large S, both in the purely Heisenberg case and also in the model with single-ion anisotropy.