Dresden 2017 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MM: Fachverband Metall- und Materialphysik
MM 5: Computational Materials Modelling: Materials at finite temperatures
MM 5.5: Vortrag
Montag, 20. März 2017, 11:15–11:30, IFW B
Investigation of low temperature features in the heat capacity of metals — •Ankit Gupta1, Bengü Tas Kavakbasi2, Biswanath Dutta1, Blazej Grabowski1, Tilmann Hickel1, Sergiy Divinski2, Gerhard Wilde2, and Jörg Neugebauer1 — 1Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany — 2Inst. of Materials Physics, Univ. of Münster, Münster, Germany
Heat capacities are often used to assess the predictive capability of computational thermodynamics, since they are experimentally directly accessible and as second derivatives very sensitive to energy changes. Finite-temperature first-principles calculations have accurately described the heat capacity of various material systems up to the melting point. In contrast, their assessment for the competition and coupling between the electronic and vibrational excitation mechanisms in the low-temperature regime is still in its infancy.
In this work, we explore this competition and coupling in the heat capacity Cp below 20 K for the example of Al and Al3Sc. In order to enhance the sensitivity with respect to low temperature features, we analyze Cp/Tn for n=0, …, 3. We show that, density functional theory successfully resolves all the features observed in the recent experimental calorimetric data, including the low-temperature limit and localization effects in the heat capacity. The relevance of peaks in the phonon density-of-states beyond the Debye level and non-adiabatic electron-phonon coupling phenomena are evaluated. All mechanisms are found to be described accurately at the level of semi-local exchange-correlation functionals.