Elastic, electronic and electrocaloric properties near room temperature in [formula omitted]-doped [formula omitted] from first-principles calculations

Abstract

Ferroelectric materials are attractive candidates for potential solid-state refrigeration. Their useful broad applications require investigation of several properties. However, the magnitude corresponding to electrocaloric effect (ECE) is seemingly too small. Insight from a theoretical approach is needed to provide support through theoretical description, leading mainly to better understanding and prediction of the electrocaloric performance, as well as additional properties that might be useful. Here, we investigate the elastic, electronic, thermoelectric, and ferroelectric properties as well as ECE of SnTiO3 by utilizing first-principles calculations and effective Hamiltonian. From the calculations toward a higher symmetry direction, the direct band gap is obtained. In addition, we have comprehensively investigated the effect of Mn-doping on the electronic and thermoelectric properties of SnTiO3 to achieve a better understanding of this material. The polarization, pyroelectric coefficient, changes in entropy ΔS and adiabatic temperature ΔT are examined in detail as a function of temperature. This work also reveals the contribution with particular attention of the applied electric field especially on the magnitude of ECE, resulting in slightly anomalous volume expansion. Typical hysteresis loops are observed to confirm the order-disorder phase transition. An enhancement route of the ECE is elucidated, which may open the door for more discussions and practical applications.