Comparison of the Vibrational Spectra of Copper Polysilicate, CuSiO<sub>3</sub>, with Those of the Prototypic Copper Polygermanate, CuGeO<sub>3</sub>

Abstract

Orthorhombic copper polysilicate, CuSiO 3 , is isotypic to the spin-Peierls compound CuGeO 3 and represents a further example of a quasi-one-dimensional spin = 1/2 antiferromagnetic Heisenberg chain system. This is a representation of the first Raman and IR/FIR spectra for CuSiO 3 , measured at room temperature on polycrystalline samples. A comparison of the optical phonons, predicted by a factor group analysis, with those observed for the CuGeO 3 prototype, is presented. A mode assignment for the silicate is given. Surface effects due to a very small crystallite size may cause additional broad bands observed in the Raman spectrum of CuSiO 3 . From the analysis of the Davydov doublet an intralayer-to-interlayer bond strength of about 40 is derived for the silicate, which is about 20% lower than for the isotypic germanate, allowing for different magnetic responses at low temperature.

Boosting CO2 Electroreduction to Multicarbon Products via Tuning of the Copper Surface Charge

“…The formation of Cu + in Cu δ+ @SiO 2 was also observed by Raman spectroscopy, whereas only Cu 2+ exists in CuSiO 3 @SiO 2 before annealing (Figure B). The peak at ∼677.2 cm –1 corresponds to the A g mode, while the band at ∼380.1 cm –1 is related with the B 2g mode of CuSiO 3 . The Raman bands at ∼295.5 and 603.1 cm –1 are attributed to Cu + species promoted by the Cu–O–Si interaction, which became more intense with increased annealing temperature .…”

Exact dimer phase with anisotropic interaction for one dimensional magnets

“…These physics needs to be explored using numerical methods. In the spin-Peierls compounds, such as CuGeO 35 , TiOCl 37 and 41 , the strong anisotropy in lattice constants (for example, in the lattice constants are: , and 36 ) is necessary to isolate a single chain (or other spin- ions) out from the three-dimensional bulk. For this reason, spatial anisotropy is inevitable and in order to describe real materials more accurately, anisotropy in the effective spin model is needed.…”

“…The MG model may be relevant to a large number of one dimensional magnets in experiments in solid materials, such as CuGeO 34 – 36 , TiOCl 37 , 38 , ) 39 , 40 , 41 , 42 and 43 , etc. In these materials, the lattice constant along one of the directions is much smaller than the other two directions, rending the couplings between the magnetic atoms along the shortest lattice constant direction is much stronger than along the other two directions, giving rise to one dimensional magnets.…”