Sitaraman, N.
Arias, T.
Farber, R.G.
Liepe, M.
Maniscalco, J.T.
Sibener, S.J.
Veit, R.D.
Ab Initio Calculations on Impurity Doped Niobium and Niobium Surfaces
JACoW Publishing
Geneva, Switzerland
978-3-95450-211-0
10.18429/JACoW-SRF2019-TUP045
English
523-526
TUP045
niobium
scattering
electron
experiment
lattice
Contribution to a conference proceedings
2019
2019-08
https://doi.org/10.18429/JACoW-SRF2019-TUP045
http://jacow.org/srf2019/papers/tup045.pdf
We develop and apply new tools to understand Nb surface chemistry and fundamental electronic processes using theoretical ab initio methods. We study the thermodynamics of impurities and hydrides in the near-surface region as well as their effect on the surface band gap. This makes it possible for experimentalists to relate changes in STM dI/dV measurements resulting from different preparations to changes in subsurface structure. We also calculate matrix elements for electron-impurity scattering in Nb for common impurities O, N, C, and H. By transforming these matrix elements into a Wannier function basis, we calculate lifetimes for a dense set of states on the Fermi surface and determine the mean free path as a function of impurity density. This technique can be generalized to calculate other scattering amplitudes and timescales relevant to SRF theory.