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DY: Fachverband Dynamik und Statistische Physik

DY 15: Condensed-matter simulations augmented by advanced statistical methodologies (joint session DY/CPP)

DY 15.2: Vortrag

Montag, 16. März 2020, 15:45–16:00, HÜL 186

Second-principles investigation of the electrocaloric properties of PbTiO₃ — •Monica Graf¹ and Jorge Iñiguez^1,2 — ¹Luxembourg Institute of Science and Technology - LIST — ²University of Luxembourg

Electrocaloric effects attract increasing attention as they provide an ecologically-friendly alternative for solid-state cooling [1] . Here we investigate the electrocaloric response of prototype ferroelectric PbTiO₃, using a second-principles approach that has already proved its ability to reproduce qualitatively the properties of this compound in bulk [2] and when embedded in various heterostructures [3]. More precisely, we perform Monte Carlo simulations at finite temperature and under applied electric field to obtain the first- and second-order electrocaloric tensor of PbTiO₃, in a temperature range including the ferroelectric transition. The first-order electrocaloric tensor can be computed from the thermal fluctuations of polarization and energy, as obtained from simulations in absence of electric field, taking advantage of Maxwell’s relations in the same way that is done in "indirect" experimental measurements of the electrocaloric effect. To access the second-order tensor, we simulate the material subject to electric fields of varying magnitude, parallel and perpendicular to the polarization. In this talk we will present and discuss our results.

References:

1. Nat Commun 9, 1827 (2018)

2. Phys. Rev. Lett. 112, 247603 (2014)

3. Nature 534, 524 (2016)