First-principles calculations of the structural, electronic, optical and elastic properties of the new phosphors, Na2ZrF6 and K2ZrF6

Two recently reported phosphor materials, Na2ZrF6 and K2ZrF6 (J. Appl. Phys. 112 (2012) 013506) are characterized using the plane-wave based first-principles calculations. The optimized crystal structure, electronic, elastic and optical properties at the ambient and elevated hydrostatic pressure are calculated. The calculated band gaps are 6.61 (5.87) eV for Na2ZrF6 (K2ZrF6), respectively. Peculiarities in the chemical bonding between the constituting elements are evaluated by calculating the effective Mulliken charges. These materials are characterized by high covalence of the Zr4+–F− bonding, as confirmed by the cross-sections of the electron density difference for both materials.

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