About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
Physical Review B
Paper
Influence of nitrogen impurities on the electronic structure of niobium
Abstract
We present x-ray photoemission results for a series of NbNx films with 0.0 x 0.2. Core and valence-band spectra show that charge is transferred from the pure metallic band to hybrid N-Nb states centered 6 eV below the Fermi edge. The x dependencies of the Fermi-level density of states nexpt(EF) and core-level-asymmetry parameters are compared to those of the superconducting transition temperature Tc and lattice constants obtained for similar samples by other workers. In particular, Tc decreases with nexpt(EF) for x<xc 0.1 after which both Tc and nexpt(EF) remain constant within experimental uncertainty. We suggest that for x>xc the metal valence electrons are not able to screen additional N impurities. The behavior of the Nb core-level widths, which measures static valence charge-density fluctuations, supports this conclusion. © 1981 The American Physical Society.