Ab-initio electronic structure, optical, dielectric and bonding properties of lizardite-1T

The structural, electronic, optical, dielectric and bonding properties of lizardite-1T [Mg3Si2O5(OH)(4)] are investigated using plane wave pseudopotential density-functional theory (DFT) method taking the generalized gradient approximation (GGA) as the exchange-correlation energy functional. The structural properties are consistent with the earlier experimental and theoretical results. The direct electronic band gap at the F-point is estimated to be 3.34 eV, which is less than the optical band gap of similar to 4.0 eV measured from the fundamental absorption edge. A remarkable optical anisotropy is observed in the optical spectra. The dielectric properties are consistent with previous theoretical calculations. Analysis of Mulliken charge and bonding population shows the coexistence of covalent and ionic bonding in the lizardite-1T and the results are also consistent with previous theoretical calculations and experimental results. (c) 2011 Elsevier B.V. All rights reserved.