A systematic density functional theory study of the electronic structure of bulk and (001) surface of transition-metals carbides
A systematic study of the bulk and surface geometrical and electronic properties of a series of transition-metalcarbides (TMC with TM=Ti, V, Zr, Nb, Mo, Hf, Ta, and W) by first-principles methods is presented. It is shown that in these materials the chemical bonding is strongly covalent, the cohesiv...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2005 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/150679 |
| Acceso en línea: | https://hdl.handle.net/2445/150679 |
| Access Level: | acceso abierto |
| Palabra clave: | Carburs Teoria del funcional de densitat Estructura electrònica Conductivitat elèctrica Carbides Density functionals Electronic structure Electric conductivity |
| Sumario: | A systematic study of the bulk and surface geometrical and electronic properties of a series of transition-metalcarbides (TMC with TM=Ti, V, Zr, Nb, Mo, Hf, Ta, and W) by first-principles methods is presented. It is shown that in these materials the chemical bonding is strongly covalent, the cohesive energies being directly related to the bonding-antibonding gap although the shift of the center of the C(2s) band related peak in the density of states with respect to diamond indicates that some metal to carbon charge transfer does also take place. The (001) face of these metalcarbides exhibits a noticeable surface rumpling which grows along the series. It is shown that neglecting surface relaxation results in very large errors on the surface energy and work function. The surface formation induces a significant shift of electronic energy levels with respect to the corresponding values in the bulk. The extent and nature of the shift can be understood from simple bonding-antibonding arguments and is enhanced by the structural rippling of this surface. |
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