Department of Physics & Astronomy and the London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, United Kingdom.
Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Phys Rev Lett. 2013 Feb 15;110(7):077401. doi: 10.1103/PhysRevLett.110.077401. Epub 2013 Feb 11.
Experimental measurements and ab initio modeling of the optical transitions in strained G-type antiferromagnetic LaCrO(3) resolve two decades of debate regarding the magnitude of the band gap and the character of the optical absorption spectrum in the visible-to-ultraviolet (up to ∼5 eV) range in this material. Using time-dependent density functional theory and accounting for thermal disorder effects, we demonstrate that the four most prominent low-energy absorption features are due to intra-Cr t(2g)-e(g) (2.7, 3.6 eV), inter-Cr t(2g)-t(2g) (4.4 eV), and interion O 2p-Cr 3d (from ∼5 eV) transitions and show that the excitation energies of the latter type can be strongly affected by the lattice strain.
实验测量和从头算建模研究了应变 G 型反铁磁 LaCrO(3)中的光学跃迁，解决了二十年来关于该材料在可见光到紫外（高达 ∼5 eV）范围内带隙大小和光学吸收光谱特征的争议。我们使用含时密度泛函理论并考虑热无序效应，证明了四个最显著的低能吸收特征归因于 Cr t(2g)-e(g)（2.7、3.6 eV）、Cr t(2g)-t(2g)（4.4 eV）之间的 intra-Cr 和 inter-Cr 跃迁以及 O 2p-Cr 3d（来自 ∼5 eV）跃迁，并表明后一种类型的激发能可以强烈受到晶格应变的影响。
