Doping-induced spin-manipulation in complex trimer system Ca${}_3$Cu${}_3$(PO${}_4$)${}_4$: A First Principles Study

Abstract

Spin-manipulated doping with magnetic (Ni) and non-magnetic (Mg) dopants constitutes the experimental attempts to obtain a singlet ground state system from the linear chain Heisenberg antiferromagnetic Cu-based $d^9$ spin-1/2 trimer compound Ca${}_3$Cu${}_3$(PO${}_4$)${}_4$ with doublet ground state. The present study is a first-principles based investigation of the effects of such doping on the spin-exchange mechanism and electronic structure of the parent compound. Site-selective doping with zero-spin dopants like Mg is proved to be more efficient than an integral spin dopant Ni in obtaining a spin-gap system with singlet ground state, as also observed in the experimental studies. Doping induced dimerized state is found to be the lowest in ground-state energy. Calculated spin exchange values along various possible paths resemble nicely with earlier experimental results.

7 pages, 6 figures, two tables

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• Calculations of Hubbard U from first-principles
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• Absence of spin gap in the superconducting ladder compound Sr_2Ca_{12}Cu_{24}O_{41}
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Cited by in corpus (1)

• Full propagation-vector star antiferromagnetic order in quantum spin trimer system $\mathrm{C}{\mathrm{a}}_3\mathrm{CuN}{\mathrm{i}}_2(\mathrm{P}{\mathrm{O}}_4{)}_4$