Two-dimensional Heisenberg behavior of J(eff)=1/2 isospins in the paramagnetic state of the spin-orbital Mott insulator Sr2IrO4.
Phys Rev Lett
; 108(24): 247212, 2012 Jun 15.
Article
de En
| MEDLINE
| ID: mdl-23004324
ABSTRACT
The dynamical correlations of J(eff)=1/2 isospins in the paramagnetic state of spin-orbital Mott insulator Sr2IrO4 were revealed by resonant magnetic x-ray diffuse scattering. We found a two-dimensional antiferromagnetic fluctuation with a large in-plane correlation length exceeding 100 lattice spacings at even 20 K above the magnetic ordering temperature. In marked contrast to the naive expectation of the strong magnetic anisotropy associated with an enhanced spin-orbit coupling, we discovered an isotropic isospin correlation that is well described by the two-dimensional S=1/2 quantum Heisenberg model. The estimated antiferromagnetic coupling constant as large as Jâ¼0.1 eV that is comparable to the small Mott gap (<0.5 eV) points out the weak and marginal Mott character of this spin-orbital entangled system.
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Collection:
01-internacional
Base de données:
MEDLINE
Langue:
En
Journal:
Phys Rev Lett
Année:
2012
Type de document:
Article
Pays d'affiliation:
Japon