Ruban, A. V.; Razumovskiy, V. I.; Körmann, F.: Erratum: Spin-wave method for the total energy of paramagnetic state (Phys. Rev. B (2012) 85 (174407)). Physical Review B 89 (17), 179901 (2014)
Hickel, T.; Grabowski, B.; Körmann, F.; Neugebauer, J.: Advancing density functional theory to finite temperatures: Methods and applications in steel design. Journal of Physics: Condensed Matter 24, 053202 (2012)
Dick, A.; Körmann, F.; Hickel, T.; Neugebauer, J.: Ab initio based determination of thermodynamic properties of cementite including vibronic, magnetic and electronic excitations. Physical Review B 84 (12), 125101 (2011)
Körmann, F.; Dick, A.; Hickel, T.; Neugebauer, J.: Role of spin quantization in determining the thermodynamic properties of magnetic transition metals. Physical Review B 83 (16), 165114 (2011)
Körmann, F.; Dick, A.; Hickel, T.; Neugebauer, J.: Rescaled Monte Carlo approach for magnetic systems: Ab initio thermodynamics of bcc iron. Physical Review B 81 (13), pp. 134425 - 134434 (2010)
Körmann, F.; Dick, A.; Hickel, T.; Neugebauer, J.: Pressure dependence of the Curie temperature in bcc iron studied by ab initio simulations. Physical Review B 79, 184406, pp. 184406-1 - 184406-5 (2009)
Körmann, F.; Kienert, J.; Schwieger, S.; Nolting, W.: Cu cap layer on Ni8/Cu(001): reorientation and Tc-shift. The European Physical Journal B 65, pp. 499 - 504 (2008)
Körmann, F.; Dick, A.; Grabowski, B.; Hallstedt, B.; Hickel, T.; Neugebauer, J.: Free energy of bcc iron: Integrated ab initio derivation of vibrational, electronic, and magnetic contributions. Physical Review B 78, 033102 (2008)
Enabling a ‘hydrogen economy’ requires developing fuel cells satisfying economic constraints, reasonable operating costs and long-term stability. The fuel cell is an electrochemical device that converts chemical energy into electricity by recombining water from H2 and O2, allowing to generate environmentally-friendly power for e.g. cars or houses…
In this project we study - together with the department of Prof. Neugebauer and Dr. Sandlöbes at RWTH Aachen - the underlying mechanisms that are responsible for the improved room-temperature ductility in Mg–Y alloys compared to pure Mg.
The wide tunability of the fundamental electronic bandgap by size control is a key attribute of semiconductor nanocrystals, enabling applications spanning from biomedical imaging to optoelectronic devices. At finite temperature, exciton-phonon interactions are shown to exhibit a strong impact on this fundamental property.
In this project, we work on a generic solution to design advanced high-entropy alloys (HEAs) with enhanced magnetic properties. By overturning the concept of stabilizing solid solutions in HEAs, we propose to render the massive solid solutions metastable and trigger spinodal decomposition. The motivation for starting from the HEA for this approach…
Efficient harvesting of sunlight and (photo-)electrochemical conversion into solar fuels is an emerging energy technology with enormous promise. Such emerging technologies depend critically on materials systems, in which the integration of dissimilar components and the internal interfaces that arise between them determine the functionality.
We have studied a nanocrystalline AlCrCuFeNiZn high-entropy alloy synthesized by ball milling followed by hot compaction at 600°C for 15 min at 650 MPa. X-ray diffraction reveals that the mechanically alloyed powder consists of a solid-solution body-centered cubic (bcc) matrix containing 12 vol.% face-centered cubic (fcc) phase. After hot compaction, it consists of 60 vol.% bcc and 40 vol.% fcc. Composition analysis by atom probe tomography shows that the material is not a homogeneous fcc–bcc solid solution