Momentum-resolved observations of the phonon instability driving geometric improper ferroelectricity in yttrium manganite.

ABSTRACT: Magnetoelectrics offer tantalizing opportunities for devices coupling ferroelectricity and magnetism but remain difficult to realize. Breakthrough strategies could circumvent the mutually exclusive origins of magnetism and ferroelectricity by exploiting the interaction of multiple phonon modes in geometric improper and hybrid improper ferroelectrics. Yet, the proposed instability of a zone-boundary phonon mode, driving the emergence of ferroelectricity via coupling to a polar mode, remains to be directly observed. Here, we provide previously missing evidence for this scenario in the archetypal improper ferroelectric, yttrium manganite, through comprehensive scattering measurements of the atomic structure and phonons, supported with first-principles simulations. Our experiments and theoreti

SUBMITTER: Bansal D 

PROVIDER: S-EPMC5750229 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature