Berlin 2015 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 17: Postersession I

MM 17.32: Poster

Monday, March 16, 2015, 18:00–20:00, Poster E

Theoretical modelling of the electronic structure of MAX phases using WIEN2k and calculation of electric field gradients — Daniel Jürgens¹, Michael Uhrmacher¹, Jose Mestnik-Filho², and •Hans Hofsäss¹ — ¹Georg-August-Universität Göttingen, II. Physikalisches Institut, Göttingen, Germany — ²Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo, Brazil

Local magnetic fields and electric field gradients at the site of probe atoms in solids can be measured with hyperfine interaction techniques and allows the investigation of the local microstructure around M- and A-sites and possible magnetic properties of MAX-phase compounds. In this work, we us the program WIEN2k to calculate electric field gradients (EFG) for In or Hf probe atoms on either A-or M-sites in different MAX phases. We present comprehensive calculations of EFGs in many 211-MAX phase compounds and compare with our experimental results from perturbed angular correlation measurements. We discuss the dependence of the A-site EFGs as function of the A-Element ranging from Al to Pb and for M-elements ranging from Ti to Hf. We find a characteristic dependence of the EFG strength on the M-element valence electron density. In most of the investigated MAX-phases we can quantitatively predict the EFG for probe atoms on A- or M-sites with good accuracy. This makes perturbed angular correlation an ideal and universal method to study electronic and also possible magnetic properties of MAX phases.