Computational structural investigation of select II-VI compounds and radtkeite (alpha-Hg3S2ClI)

Steven Matthew Sellepack, University of Texas at El Paso

Abstract

Computational modeling of novel materials is an increasingly powerful tool being used in the development of advanced materials and their device applications. This course of study has been undertaken to discern: (1) the present state of computational simulation of materials; (2) the present ability of computational hardware and software to model new materials; and (3) the ability to apply computational modeling to a relatively poorly studied solid state system, namely mercury(II) chalcogenide halides. Initial interest in this system was fostered by the reported tubular growth of radtkeite (α-Hg3S2ClI), which can display a tubular crystal habit tens of micrometers long and micrometers in diameter. ^ To validate that the structures and energies of mercury(II) chalcogenides could be accurately modeled the pressure induced phase transitions in the HgS system were studied using ab initio DF (density functional) calculations. ^ Select MS (M = Ca, Ba, Zn, Cd, Hg, S) compounds were modeled in the cinnabar and zinc-blende structures to discern that they could be accurately modeled. A qualitative description of the MS compounds in the cinnabar structure is provided along with reasoning concerning their relative stability. ^ Three possible radtkeite structures were identified using a brute force methodology of powder x-ray diffraction pattern simulation and then modeled using A initio DF calculations. The cell based upon the γ-Hg3S 2Cl2 structure was deemed as the best match. ^ This study has validated that computational methods can be used for structural prediction of mercury(II) chalcogenides and chalcogenide halides, however certain methods produced unacceptable results. ^ Materials application statement. This study seeks to discern halogen interactions within II–VI semiconducting materials, namely the mercury(II) chalcogenides. The strategy and methodology of the research will be to invoke computer simulations. The ultimate goal being the correlation of atomic to bulk scale properties of materials, and the increased speed of new materials discovery and implementation. (Abstract shortened by UMI.) ^

Subject Area

Mineralogy|Chemistry, Inorganic|Engineering, Materials Science

Recommended Citation

Sellepack, Steven Matthew, "Computational structural investigation of select II-VI compounds and radtkeite (alpha-Hg3S2ClI)" (2000). ETD Collection for University of Texas, El Paso. AAI9997677.
http://digitalcommons.utep.edu/dissertations/AAI9997677

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