Steven Achilles

Dr. Steven Achilles is a researcher affiliated with the Institute of Physics at Martin Luther University Halle-Wittenberg, working within the Faculty of Natural Sciences II (Chemistry, Physics, and Mathematics). His research focuses on theoretical physics, particularly electronic structures and transport properties in mesoscopic systems and magnetic nanocontacts.

Doctoral Thesis:

• Developed a self-consistent method combining non-equilibrium Green functions (Keldysh formalism) with the Korringa-Kohn-Rostoker (KKR) multiple scattering approach to model planar tunnel junctions, nanocontacts, and scanning-tunneling-like geometries under bias voltage. This technique avoids supercell artifacts and improves conductance/current calculations.

Diploma Thesis:

• Conducted ab initio studies of electronic transport in cobalt (Co) and nickel (Ni) magnetic nanocontacts using density functional theory and the Landauer approach (Baranger-Stone formulation). Investigated ballistic magnetoresistance ratios (BMR) in Co atomic chains and symmetry-breaking effects in Ni nanocontacts, achieving good agreement with experimental data.

Research Methodology: specializes in computational modeling of nanoscale systems, leveraging advanced quantum mechanical frameworks like DFT, Keldysh formalism, and KKR multiple scattering methods to analyze charge relaxation, potential landscape changes, and transport phenomena in non-translationally invariant systems.