Abstract
It has been demonstrated recently that the stoichiometry of rocksalt TaN can be tuned by (formula presented) pressure and temperature, yielding material that ranges from highly conductive to insulating. Using density functional theory, we investigate the atomic and electronic structure and formation energy of defective TaN structures. The calculations predict that Ta and N vacancies form under N-rich and N-poor conditions, respectively, where the presence of Ta vacancies reduce the density of states (DOS) around the Fermi level (formula presented) We also studied the (formula presented) and (formula presented) structures which occur in nature. The former phase, consisting of an ordered arrangement of Ta vacancies, also exhibits a notable decrease in the DOS at (formula presented) while the latter is a semiconductor with a band gap of 1.5 eV within the local density approximation. Our results suggest that the formation of Ta-deficient structures is directly related to the metal-to-insulator transition.
| Original language | English |
|---|---|
| Journal | Physical Review B - Condensed Matter and Materials Physics |
| Volume | 67 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Feb 28 2003 |
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ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
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Metallic to insulating nature of (formula presented) Role of Ta and N vacancies. / Stampfl, C.; Freeman, Arthur J.
In: Physical Review B - Condensed Matter and Materials Physics, Vol. 67, No. 6, 28.02.2003.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Metallic to insulating nature of (formula presented) Role of Ta and N vacancies
AU - Stampfl, C.
AU - Freeman, Arthur J
PY - 2003/2/28
Y1 - 2003/2/28
N2 - It has been demonstrated recently that the stoichiometry of rocksalt TaN can be tuned by (formula presented) pressure and temperature, yielding material that ranges from highly conductive to insulating. Using density functional theory, we investigate the atomic and electronic structure and formation energy of defective TaN structures. The calculations predict that Ta and N vacancies form under N-rich and N-poor conditions, respectively, where the presence of Ta vacancies reduce the density of states (DOS) around the Fermi level (formula presented) We also studied the (formula presented) and (formula presented) structures which occur in nature. The former phase, consisting of an ordered arrangement of Ta vacancies, also exhibits a notable decrease in the DOS at (formula presented) while the latter is a semiconductor with a band gap of 1.5 eV within the local density approximation. Our results suggest that the formation of Ta-deficient structures is directly related to the metal-to-insulator transition.
AB - It has been demonstrated recently that the stoichiometry of rocksalt TaN can be tuned by (formula presented) pressure and temperature, yielding material that ranges from highly conductive to insulating. Using density functional theory, we investigate the atomic and electronic structure and formation energy of defective TaN structures. The calculations predict that Ta and N vacancies form under N-rich and N-poor conditions, respectively, where the presence of Ta vacancies reduce the density of states (DOS) around the Fermi level (formula presented) We also studied the (formula presented) and (formula presented) structures which occur in nature. The former phase, consisting of an ordered arrangement of Ta vacancies, also exhibits a notable decrease in the DOS at (formula presented) while the latter is a semiconductor with a band gap of 1.5 eV within the local density approximation. Our results suggest that the formation of Ta-deficient structures is directly related to the metal-to-insulator transition.
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U2 - 10.1103/PhysRevB.67.064108
DO - 10.1103/PhysRevB.67.064108
M3 - Article
AN - SCOPUS:85038956535
VL - 67
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 6
ER -