TY - JOUR

T1 - Spin-12 heisenberg antiferromagnet on an anisotropic kagome lattice

AU - Li, P. H.Y.

AU - Bishop, R. F.

AU - Campbell, C. E.

AU - Farnell, D. J.J.

AU - Götze, O.

AU - Richter, J.

PY - 2012/12/4

Y1 - 2012/12/4

N2 - We use the coupled-cluster method to study the zero-temperature properties of an extended two-dimensional Heisenberg antiferromagnet formed from spin-12 moments on an infinite spatially anisotropic kagome lattice of corner-sharing isosceles triangles, with nearest-neighbor bonds only. The bonds have exchange constants J1>0 along two of the three lattice directions and J2≡κJ1>0 along the third. In the classical limit, the ground-state (GS) phase for κ<12 has collinear ferrimagnetic (Néel′) order where the J2-coupled chain spins are ferromagnetically ordered in one direction with the remaining spins aligned in the opposite direction, while for κ>12 there exists an infinite GS family of canted ferrimagnetic spin states, which are energetically degenerate. For the spin-12 case, we find that quantum analogs of both these classical states continue to exist as stable GS phases in some regions of the anisotropy parameter κ, namely, for 0<κ<κc1 for the Néel′ state and for (at least part of) the region κ>κc2 for the canted phase. However, they are now separated by a paramagnetic phase without either sort of magnetic order in the region κc1<κ<κc2, which includes the isotropic kagome point κ=1 where the stable GS phase is now believed to be a topological (Z2) spin liquid. Our best numerical estimates are κc1=0.515±0.015 and κc2= 1.82±0.03.

AB - We use the coupled-cluster method to study the zero-temperature properties of an extended two-dimensional Heisenberg antiferromagnet formed from spin-12 moments on an infinite spatially anisotropic kagome lattice of corner-sharing isosceles triangles, with nearest-neighbor bonds only. The bonds have exchange constants J1>0 along two of the three lattice directions and J2≡κJ1>0 along the third. In the classical limit, the ground-state (GS) phase for κ<12 has collinear ferrimagnetic (Néel′) order where the J2-coupled chain spins are ferromagnetically ordered in one direction with the remaining spins aligned in the opposite direction, while for κ>12 there exists an infinite GS family of canted ferrimagnetic spin states, which are energetically degenerate. For the spin-12 case, we find that quantum analogs of both these classical states continue to exist as stable GS phases in some regions of the anisotropy parameter κ, namely, for 0<κ<κc1 for the Néel′ state and for (at least part of) the region κ>κc2 for the canted phase. However, they are now separated by a paramagnetic phase without either sort of magnetic order in the region κc1<κ<κc2, which includes the isotropic kagome point κ=1 where the stable GS phase is now believed to be a topological (Z2) spin liquid. Our best numerical estimates are κc1=0.515±0.015 and κc2= 1.82±0.03.

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U2 - 10.1103/PhysRevB.86.214403

DO - 10.1103/PhysRevB.86.214403

M3 - Article

AN - SCOPUS:84871079491

SN - 1098-0121

VL - 86

JO - Physical Review B - Condensed Matter and Materials Physics

JF - Physical Review B - Condensed Matter and Materials Physics

IS - 21

M1 - 214403

ER -