Metallic to insulating nature of TaNx

Role of Ta and N vacancies

C. Stampfl, Arthur J Freeman

Research output: Contribution to journalArticle

81 Citations (Scopus)

Abstract

It has been demonstrated recently that the stoichiometry of rocksalt TaN can be tuned by N2 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 (EF). We also studied the Ta4N5 and Ta3N5 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 EF, 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 Tadeficient structures is directly related to the metal-to-insulator transition.

Original languageEnglish
Article number064108
Pages (from-to)641081-641087
Number of pages7
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume67
Issue number6
Publication statusPublished - Feb 1 2003

Fingerprint

Vacancies
Crystal atomic structure
Local density approximation
energy of formation
Fermi level
atomic structure
Stoichiometry
Electronic structure
Density functional theory
stoichiometry
Energy gap
Metals
insulators
Semiconductor materials
density functional theory
electronic structure
approximation
metals
Temperature
temperature

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Metallic to insulating nature of TaNx : Role of Ta and N vacancies. / Stampfl, C.; Freeman, Arthur J.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 67, No. 6, 064108, 01.02.2003, p. 641081-641087.

Research output: Contribution to journalArticle

@article{2cc6f3017aea46669cf118b1a1777e43,
title = "Metallic to insulating nature of TaNx: Role of Ta and N vacancies",
abstract = "It has been demonstrated recently that the stoichiometry of rocksalt TaN can be tuned by N2 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 (EF). We also studied the Ta4N5 and Ta3N5 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 EF, 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 Tadeficient structures is directly related to the metal-to-insulator transition.",
author = "C. Stampfl and Freeman, {Arthur J}",
year = "2003",
month = "2",
day = "1",
language = "English",
volume = "67",
pages = "641081--641087",
journal = "Physical Review B-Condensed Matter",
issn = "1098-0121",
publisher = "American Physical Society",
number = "6",

}

TY - JOUR

T1 - Metallic to insulating nature of TaNx

T2 - Role of Ta and N vacancies

AU - Stampfl, C.

AU - Freeman, Arthur J

PY - 2003/2/1

Y1 - 2003/2/1

N2 - It has been demonstrated recently that the stoichiometry of rocksalt TaN can be tuned by N2 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 (EF). We also studied the Ta4N5 and Ta3N5 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 EF, 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 Tadeficient 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 N2 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 (EF). We also studied the Ta4N5 and Ta3N5 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 EF, 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 Tadeficient structures is directly related to the metal-to-insulator transition.

UR - http://www.scopus.com/inward/record.url?scp=0037302531&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037302531&partnerID=8YFLogxK

M3 - Article

VL - 67

SP - 641081

EP - 641087

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 6

M1 - 064108

ER -