Thermoelectric properties and electronic structure of Cr(Mo,V)Nx thin films studied by synchrotron and lab-based X-ray spectroscopy

Abstract

Chromium-based nitrides are used in hard, resilient coatings, and show promise for thermoelectric applications due to their combination of structural, thermal, and electronic properties. Here, we investigated the electronic structures and chemical bonding correlated to the thermoelectric properties of epitaxially grown chromium-based multicomponent nitride Cr(Mo,V)Nx thin films. Due to minuscule N vacancies, finite population of Cr 3d and N 2p states appear at the Fermi level and diminishes the band opening for Cr0.51N0.49. Incorporating holes by alloying V in N deficient CrN matrix results in enhanced thermoelectric power factor with marginal change in the charge transfer of Cr to N compared to Cr0.51N0.49. Further alloying Mo isoelectronic to Cr increases the density of states across the Fermi level due to hybridization of the (Cr, V) 3d and Mo 4d-N 2p states in Cr(Mo,V)Nx. The hybridization effect with reduced N 2p states off from stoichiometry drives the system towards metal like electrical resistivity and reduction in Seebeck coefficient compensating the overall power factor still comparable to Cr0.51N0.49. The N deficiency also depicts a critical role in reduction of the charge transfer from metal to N site. The present work envisages ways for enhancing thermoelectric properties through electronic band engineering by alloying and competing effects of N vacancies.

arXiv comment28 pages, 11 figures, 2 tables

References in corpus (17)

• Resonant Inelastic X-ray Scattering Studies of Elementary Excitations
• XAFS spectroscopy. I. Extracting the fine structure from the absorption spectra
• Effect of magnetic disorder and strong electron correlations on the thermodynamics of CrN
• Magnetic stress as a driving force of structural distortions: the case of CrN
• Structural stability and thermodynamics of CrN magnetic phases from ab initio and experiment
• Evidence for a correlated insulator to antiferromagnetic metal transition in CrN
• Anomalous phonon lifetime shortening in paramagnetic CrN caused by magneto-lattice coupling: A combined spin and ab initio molecular dynamics study
• Effect of ion-implantation-induced defects and Mg dopants on thermoelectric properties of ScN
• Electronic structure of CrN: A comparison between different exchange correlation potentials
• Energy Dependence of Cu L2,3 Satellites using Synchrotron Excited X-ray Emission Spectroscopy
• The role of N defects in paramagnetic CrN at finite temperatures from first-principles
• Structural and Magnetic Phase Transitions in Chromium Nitride Thin Films Grown by RF Nitrogen Plasma Molecular Beam Epitaxy
• Electronic structure investigation of the cubic inverse perovskite Sc3AlN
• Secondary Phase Limited Metal-Insulator Phase Transition in Chromium Nitride Thin Films
• Anisotropic electronic phase transition in CrN epitaxial thin films
• P-type behavior of CrN thin films by control of point defects
• All 3d electron-hole bilayers in CrN/MgO(111) multilayers