Regensburg 2016 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: Hybrid and Perovskite Photovoltaics II (joint session CPP/DF/DS/HL, organized by CPP)

CPP 21.5: Talk

Tuesday, March 8, 2016, 12:00–12:15, H37

Tunable ferroelectric polarization and its interplay with spin-orbit coupling in tin iodide perovskite — Alessandro Stroppa¹, •Domenico Di Sante², Paolo Barone¹, Menno Bokdam³, Georg Kresse³, Cesare Franchini³, Myung-Hwan Whangbo⁴, and Silvia Picozzi¹ — ¹CNR-SPIN L’aquila, Italy — ²CNR-SPIN L’aquila, Italy and Wuerzburg University — ³Faculty of Physics, Center for Computational Materials Science, University of Vienna, Wien, Austria — ⁴Department of Chemistry, North Carolina State University, USA

Ferroelectricity is a potentially crucial issue in halide perovskites, breakthrough materials in photovoltaic research. Using density functional theory simulations and symmetry analysis, we show that the lead-free perovskite iodide (FA)SnI₃, containing the planar formamidinium cation FA, (NH2CHNH2)⁺, is ferroelectric. In fact, the perpendicular arrangment of FA planes, leading to a weak polarization, is energetically more stable than parallel arrangements of FA planes, being either antiferroelectric or strong ferroelectric. Moreover, we show that the weak and strong ferroelectric states with the polar axis along different crystallographic directions are energetically competing. Intriguingly, the relatively strong spin-orbit couling in noncentrosymmetric (FA)SnI₃ gives rise to a co-existence of Rashba and Dresselhaus effects and to a spin texture that can be induced, tuned and switched by an electric field controlling the ferroelectric state.

A. Stroppa, D. Di Sante et al., Nature Commun. 5, 5900 (2014)