Vacancy filling effect in thermoelectric NbO. (2nd March 2015)

• Record Type: Journal Article
• Authors: Music, Denis; Geyer, Richard W; Bliem, Pascal; Hans, Marcus; Primetzhofer, Daniel
• Is Part Of: Journal of physics. Volume 27:Number 11(2015)
• Publication Date: 2015-03-02
• Subjects: oxynitrides -- thermoelectric properties -- density functional theory; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/0953-8984/27/11/115501
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Using density functional theory, we have systematically explored the 1 a and 1 b vacancy filling in NbO (space group Pm -3 m ) with Nb and N, respectively, to design compounds with large Seebeck coefficients. The most dominating effect was identified for filling of 1 b Wyckoff sites with N giving rise to a fivefold increase in the Seebeck coefficient. This may be understood based on the electronic structure. Nb d —nonmetal p hybridization induces quantum confinement and hence enables the enhancement of the Seebeck coefficient. This was validated by measuring the Seebeck coefficient of reactively sputtered thin films. At 800 °C these electrically conductive oxynitrides exhibit the Seebeck coefficient of −70 µ V K −1, which is the largest absolute value ever reported for these compounds.