Seminar FO

Drage kolegice i kolege,
zadovoljstvo nam je najaviti sljedeći seminar Fizičkog odsjeka:

Dear colleagues,
it is our pleasure to invite you to the following seminar of the Department
of Physics:

utorak/Tuesday *27.6.2023. 11:15, F201*

Microscopic origin of ferroelectricity in hybrid organic-inorganic
perovskites

Alessandro Stroppa, CNR-SPIN Institute, Italy

Hybrid Organic-Inorganic Perovskites (HOIPs) are introducing new directions
in the materials science landscape. In this talk, we will discuss the
intriguing origin of ferroelectricity in HOIPs. In particular, we highlight
the hybrid improper mechanism where Jahn-Teller cooperative distortions are
subtly coupled to inversion symmetry breaking giving rise to a switchable
electric polarization. Symmetry invariants theory permits to predict a
magneto-electric coupling which has been recently confirmed by experiments.
We propose further examples of the complex multifunctional behaviour
arising from the organic and inorganic dual nature as well as from the
interplay between ferroelectricity and spin-related properties in hybrid
perovskites, by discussing a complex and recently synthesized ferroelectric
layered two-dimensional HOIP, (AMP)PbI4 (AMP=4-aminomethyl-piperidinium).
We report a new effect, i.e., an extraordinarily large Rashba anisotropy
that is tunable by ferroelectric polarization: as polarization is reversed,
not only the spin texture is inverted, but also the major and minor axes of
the Rashba anisotropy ellipse in k-space are interchanged, i.e. a
pseudo-rotation. A k⋅p model Hamiltonian and symmetry-mode analysis reveal
a quadrilinear coupling between the cation rotation modes responsible for
the Rashba ellipse pseudo-rotations, the framework rotation, and the
polarization.

A formatted abstract is attached.

Lijepi pozdrav / best regards

Sanjin Benić & Damjan Pelc