GROUND-STATE PROPERTIES OF BORON-DOPED DIAMOND
Zarechnaya E.Yu., Isaev E.I., Simak S.I., Vekilov Yu.Kh., Dubrovinsky L., Dubrovinskaia N., Abrikosov I.A.

Received: March 12, 2007

PACS: 61.05.cp, 61.72.S-, 71.20.-b, 74.70.Ad

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Boron-doped diamond undergoes an insulator-metal or even a superconducting transition at some critical value of the dopant concentration. We study the equilibrium lattice parameter and bulk modulus of boron-doped diamond experimentally and in the framework of the density functional method for different levels of boron doping. We theoretically consider the possibility for the boron atoms to occupy both substitutional and interstitial positions and investigate their influence on the electronic structure of the material. The obtained data suggest that boron softens the lattice, but softening due to substitutions of carbon with boron is much weaker than due to incorporation of boron into interstitial positions. Theoretical results obtained for substitution of carbon are in a very good agreement with our experiment. We present a concentration dependence of the lattice parameter in boron-doped diamond, which can be used for an identification of the levels of boron doping in future experiments.