Structural, electrical, and thermoelectric properties of distorted 1T-Ta1−xNbxTe2 single crystals. (19th January 2015)

• Record Type: Journal Article
• Authors: Liu, Y.; Lu, W. J.; Shao, D. F.; Zu, L.; Kan, X. C.; Song, W. H.; Sun, Y. P.
• Is Part Of: Europhysics letters. Volume 109:Number 1(2015:Jan.)
• Publication Date: 2015-01-19
• Subjects: 74.70.-b -- 74.25.F- -- 74.62.Dh; Physics -- Periodicals; Electronic journals; 530.05
• DOI: 10.1209/0295-5075/109/17003
• Languages: English
• ISSNs: 0295-5075

Abstract

Abstract: A series of isovalent Nb-substituted Ta1− x Nb x Te2 ( ) single crystals, which crystallizes in a monoclinically distorted CdI2 -type structure with the space group, were grown by the chemical-vapor-transport (CVT) method. For TaTe2 ( ), a first-order transition at is observed by heat capacity measurement, accompanying with an anomaly in electrical resistivity, Hall resistivity, and especially, the sign change of thermoelectric power, implying the multi-band transport. This transition can be gradually suppressed by isovalent Nb substitution and disappears as, and correspondingly, an enhancement of electronic density of states (DOS) near the Fermi level is obtained. In addition, the local Ta-Te/Ta-Ta bonding instability may play an important role for the structural phase transition of TaTe2 .