Raman scattering for triangular lattices spin-1/2 Heisenberg antiferromagnets

• Published in: Journal of physics. Condensed matter Vol. 19; no. 14; pp. 145243 - 145243 (6)
• Main Authors: Vernay, F, Devereaux, T P, Gingras, M J P
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Bristol IOP Publishing 11.04.2007; Institute of Physics
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; General theory and models of magnetic ordering; Infrared and raman spectra and scattering; Magnetic properties and materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Organic compounds, polymers; Physics; Finite size effect; Polarization; Ground states; Organic conductors; Antiferromagnetic materials; Heisenberg model; Cesium chlorides; Cyano complex; Lanczos method; Triangular lattices; BEDT-TTF; Copper chlorides; Square lattices; Exchange interactions; Copper complexes; Quantum fluctuation
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/19/14/145243

Motivated by various spin-1/2 compounds like Cs2CuCl4 or kappa-(BEDT-TTF)2Cu2(CN)3, we derive a Raman-scattering operator a la Shastry and Shraiman for various geometries. For T = 0, the exact spectra are computed by the Lanczos algorithm for finite-size clusters. We perform a systematic investigation as a function of J2/J1, the exchange constant ratio: ranging from J2 = 0, the well known square-lattice case, to J2/J1 = 1 the isotropic triangular lattice. We discuss the polarization dependence of the spectra and show how it can be used to detect precursors of the instabilities of the ground state against quantum fluctuations.