Electronic and structural properties of orthorhombic KTiOPO₄ and related isomorphic materials

Abstract

PACS 61.50. Ah, 61.66.Fn, 61.72.Ji, 71.15.Nc, 71.20.Ps Ab-initio electronic structure calculations using the local density (LDA) and generalized gradient approximations (GGA) are undertaken on Potassium Titanyl Phosphate (KTP) and isomorphic materials. The crystal structure is better predicted using one of the GGA approximations. The affect of Rb replacing K on the essential TiO 6 and PO 4 blocks of the alloyed system are investigated as are affects of AsO 4 replacing PO 4 . It is observed that the asymmetry in the K -Rb alloy very slightly affects the electronic properties of the material. Electronic charge density distributions clearly show the cation conduction channels, with changes found to occur between the different structural isomorphs. A calculated density of electronic states shows the importance of Ti -O interactions around the Fermi energy that lead to important laser properties.

Electronic structure of KTiOAsO4: A comparative study by the full potential linearized augmented plane wave method, X-ray emission spectroscopy and X-ray photoelectron spectroscopy

“…It should be mentioned that, the electronic structure of KTP was studied theoretically in a series of works [17][18][19][20]. Results of these works regarding main features of electronic properties of potassium titanyl phosphate are in agreement.…”

“…The presence of such interactions leads to important laser properties of KTP [20]. As Lowther et al [20] have established, the laser transitions occurring in KTP and related isomorphic materials involve transitions between O 2p-and Ti 3d-like states. Due to the GGA calculations [20], total energy changes from the value −120.1188 to the value −110.4113 eV/f.u.…”

“…Ching and Xu [19] based on first-principles self-consistent calculations of the electronic structure of KTP employing the orthogonalized linear combinations of atomic orbitals (OLCAO) method have shown that the presence of short Ti-O bonds in potassium titanyl phosphate makes a profound effect on its electronic structure. Furthermore, Lowther et al [20] based on generalized gradient approximations (GGA) calculations have stressed also the importance of Ti-O interactions around the Fermi energy, E F , of KTP. The presence of such interactions leads to important laser properties of KTP [20].…”

“…Furthermore, Lowther et al [20] based on generalized gradient approximations (GGA) calculations have stressed also the importance of Ti-O interactions around the Fermi energy, E F , of KTP. The presence of such interactions leads to important laser properties of KTP [20]. As Lowther et al [20] have established, the laser transitions occurring in KTP and related isomorphic materials involve transitions between O 2p-and Ti 3d-like states.…”

Potassium titanyl phosphate (KTP) quasiparticle energies and optical response

“…The valence-band maximum (VBM) is located at the T point, slightly (28 meV) above the highest occupied state at Γ. It is separated from the conduction-band minimum (CBM) at Γ by an energy gap of 2.97 eV, in close agreement with earlier DFT-GGA calculations by Lowther et al [18]. The VBM and CBM orbital characters are shown in figure 4.…”