Sr2Cu(PO4)2: A real material realization of the one-dimensional nearest neighbor Hei

Abstract

We present evidence that crystalline Sr2Cu(PO4)2 is a nearly perfect one-dimensional (1D) spin-1/2 anti-ferromagnetic Heisenberg model (AHM) chain compound with nearest neighbor only exchange. We undertake a broad theoretical study of the magnetic properties of this compound using first principles (LDA, LDA+U calculations), exact diagonalization and Bethe-ansatz methodologies to decompose the individual magnetic contributions, quantify their effect, and fit to experimental data. We calculate that the conditions of one-dimensionality and short-ranged magnetic interactions are sufficiently fulfilled that Bethe's analytical solution should be applicable, opening up the possibility to explore effects beyond the infinite chain limit of the AHM Hamiltonian. We begin such an exploration by examining some extrinsic effects such as impurities and defects.

Electronic structure of spin-12Heisenberg antiferromagnetic systems:Ba2CuSalunke1, Ahsan2, Nath3 et al. 2007Phys. Rev. B150180View full textAdd to dashboardCite

“…Recently, these hoppings were also calculated by adopting a fitting procedure. 19 Although the trends among the hoppings obtained by fitting the conduction band agree with our ab initio results, the magnitude as well as the range of the hoppings are exaggerated in the fitting scheme.…”

CuII materials—From crystal chemistry to magnetic model compounds

“…From the approximate solution of such models, the magnetic ground state and its excitations can be estimated. In the following, this procedure is demonstrated exemplarily for the compounds Sr 2 Cu(PO 4 ) 2 [16] and ACu 2 O 2 (AQNa, Li) [17][18][19][20][21].…”

“…Isolated CuO 4 squares (Fig. 2a) can be present in connection with complex anions such as sulfate or phosphate groups like in the crystal structures of CuPbSO 4 (OH) 2 and Sr 2 Cu(PO 4 ) 2 [16], respectively. In other compounds CuO 4 squares may share common oxygen positions forming structural arrangements as sketched in Fig.…”

Quasi-One-Dimensional Magnetism Driven by Unusual Orbital Ordering inCuSb2O6

“…LSDA+U calculations of differently ordered spin configurations (FM and AFM) were performed to obtain an effective exchange constant, J nn 2 by mapping the energies obtained from the calculations to a Heisenberg model (neglecting the other J's since they are small according to the TBM), H = i,j J ij S i ·S j which leads to E f m − E af m = 2J ∼ 140 K, in good comparison to the value of about 100K obtained in susceptibility experiments. [16] The slight overestimation of the leading exchange is rather typical for this type of calculation [3] and also somewhat dependent on the choice of U which is not exactly known. We obtain a charge transfer gap of 2.2 eV which is consistent with the green color of the sample.…”

“…This way, the low-dimensional magnetic properties of a compound depend crucially on the arrangements of these Cu-O 4 units forming different networks, for instance (i) quasi 1D chains from isolated (i.e. Sr 2 Cu(PO 4 ) 2 [2,3]) edge-sharing (i.e. Li 2 CuO 2 [4,5])or corner-sharing (i.e.…”