1 research outputs found
Atomic Mechanism of Hybridization-Dependent Surface Reconstruction with Tailored Functionality in Hexagonal Multiferroics
The
broken symmetry along with anomalous defect structures and charging
conditions at multiferroics surface can alter both crystal structures
and electronic configurations, bringing in emergent physical properties.
Extraordinary surface states are induced into original mutually coupled
order parameters in such strongly correlated oxides, which flourish
in diverse properties but remain less explored. Here, we report the
peculiar surface ferroelectric states and reconfigurable functionalities
driven by the relaxation of surface and consequent changes in O 2p
and Y 4d orbital (p–d) hybridization within a representative
hexagonal multiferroics, YMnO<sub>3</sub>. An unprecedented surface
reconstruction is achieved by tailored p–d hybridization coupling
with in-plane oxygen vacancies, which is atomically revealed on the
basis of the advantages of state-of-the-art aberration-corrected (scanning)
transmission electron microscopy. Further ab initio density functional
theory calculations verify the key roles of in-plane oxygen vacancies
in modulating polarization properties and electronic structure, which
should be regarded as the atomic multiferroic element. This surface
configuration is found to induce tunable functionalities, such as
surface ferromagnetism and conductivity. Meanwhile, the controversial
origin of improper ferroelectricity that is unexpectedly free from
critical size has also been atomically unraveled. Our findings provide
new insights into the design and implementation of surface chemistry
devices by simply controlling the oxygen stoichiometry, greatly advance
our understandings of surface science in strongly correlated oxides,
and enable exciting innovations and new technological functionality
paradigms