Electronic structure of spin-12Heisenberg antiferromagnetic systems:Ba2Cu

Abstract

We have employed first principles calculations to study the electronic structure and magnetic properties of the low-dimensional phosphates, Ba2Cu(PO4)2 and Sr2Cu(PO4)2. Using the selfconsistent tight binding linearized muffin-tin orbital (TB-LMTO) method and the N th order muffin tin orbital (NMTO) method we have calculated the various intrachain as well as the interchain hopping parameters between the magnetic ions (Cu 2+ ) for both the compounds. We find that the nearest-neighbor intrachain hopping (t) is the dominant interaction suggesting the compounds to be indeed one-dimensional. Our analysis of the band dispersion, orbital projected band structures and the hopping parameters confirms that the Cu 2+ -Cu 2+ super-super exchange interaction takes place along the crystallographic b-direction mediated by O-P-O. We have also analyzed in details the origin of short range exchange interaction for these systems. Our ab-initio estimate of the ratio of the exchange interaction of Sr2Cu(PO4)2 to that of Ba2Cu(PO4)2 compares excellently with available experimental results.

Expansion of Vibration-Based Sphere-Pack Technology to Binary Mixture Including Irregular Particles

“…This Hamiltonian is used to model quasi-one-dimensional magnetic compounds [72] and Josephson-junction-arrays [73,74]. It is also a fairly good approximation for couplings which decay exponentially with the qubit distance-as arising, for instance, in semiconductor quantum dot arrays [75], or which decay cubically-as in dipolarly coupled solid or liquid-crystal NMR spin systems [1,3,76] and electrons floating on helium [77,78].…”

Reply to “Comment on ‘Electronic structure of spin-12Heisenberg antiferromagnetic systems:Ba2CuSalunke1, Ahsan2, Nath3 et al. 2009Phys. Rev. BSelf Cite3040View full textAdd to dashboardCite

“…1. Salunke et al 1 merely speculated that small interchain hoppings may be important for the low-temperature properties of these compounds. They tried to verify the above speculation using exact diagonalization studies on small systems which has been criticized by the authors of the comment.…”

“…The first comment pertains to the magnitude of the leading hopping parameter t 1 obtained by Salunke et al 1 This hopping is somewhat underestimated in the work by Salunke et al 1 in comparison to the work by Johannes et al 2 and the authors of the comment, by a series of full-potential densityfunctional calculations, argue that this is due to the use of tight-binding linear muffin tin orbital ͑TB-LMTO͒ method within atomic sphere approximation ͑ASA͒ for the calculation of the band dispersion in Ref. 1.…”

“…It is also to be noted that in the absence of a reliable scheme to obtain U eff , an accurate evaluation of the hopping parameters for these strongly correlated Heisenberg antiferromagnetic ͑HAF͒ systems is presently less important as it does not provide accurate enough estimate for the exchange integrals J ij crucial to model these systems. In view of the above, the main emphasis of the work by Salunke et al 1 has been to understand the origin of the dominant nearest-neighbor hopping parameter ͑t 1 ͒ crucial for the unique one-dimensional properties of these systems, using an ab initio scheme where the use of TB-LMTO ASA method is found to be adequate for the description of band dispersion. Using NMTO downfolding scheme in the framework of TB-LMTO ASA, Salunke et al 1 not only filter out the low-energy band dispersion but also obtain the corresponding Wannier functions that give rise to these bands thereby providing a direct access to the origin of the various hopping integrals crucial to understand the physics of these systems.…”

“…In view of the above, the main emphasis of the work by Salunke et al 1 has been to understand the origin of the dominant nearest-neighbor hopping parameter ͑t 1 ͒ crucial for the unique one-dimensional properties of these systems, using an ab initio scheme where the use of TB-LMTO ASA method is found to be adequate for the description of band dispersion. Using NMTO downfolding scheme in the framework of TB-LMTO ASA, Salunke et al 1 not only filter out the low-energy band dispersion but also obtain the corresponding Wannier functions that give rise to these bands thereby providing a direct access to the origin of the various hopping integrals crucial to understand the physics of these systems. The second comment by Rosner et al 3 is on the exact diagonalization studies in Ref.…”