Babkevich, P.Katukuri, Vamshi M.Fak, B.Rols, S.Fennell, T.Pajic, D.Tanaka, H.Pardini, T.Singh, R. R. P.Mitrushchenkov, A.Yazyev, O. V.Rønnow, Henrik M.2017-01-242017-01-242017-01-24201610.1103/PhysRevLett.117.237203https://infoscience.epfl.ch/handle/20.500.14299/133541WOS:000389032600012Sr2CuTeO6 presents an opportunity for exploring low-dimensional magnetism on a square lattice of S = 1/2 Cu2+ ions. We employ ab initio multireference configuration interaction calculations to unravel the Cu2+ electronic structure and to evaluate exchange interactions in Sr2CuTeO6. The latter results are validated by inelastic neutron scattering using linear spin-wave theory and series-expansion corrections for quantum effects to extract true coupling parameters. Using this methodology, which is quite general, we demonstrate that Sr2CuTeO6 is an almost ideal realization of a nearest-neighbor Heisenberg antiferromagnet but with relatively weak coupling of 7.18(5) meV.MPBHtext::journal::journal article::research article