Polar magnetic states are realized in pseudocubic manganite thin films fabricated on high-index substrates, in which a Jahn-Teller (JT) distortion remains an active variable. Several types of orbital-orders were found to develop large optical second harmonic generation, signaling broken-inversion-symmetry distinct from their bulk forms and films on (100) substrates. The observed symmetry-lifting and first-principles calculation both indicate that the modified JT q2 mode drives Mn-site off-centering upon orbital order, leading to the possible cooperation of "Mn-site polarization" and magnetism.
@article{arxiv.1112.0882,
title = {Polar Antiferromagnets Produced with Orbital-Order},
author = {Naoki Ogawa and Yasushi Ogimoto and Yoshiaki Ida and Yusuke Nomura and Ryotaro Arita and Kenjiro Miyano},
journal= {arXiv preprint arXiv:1112.0882},
year = {2015}
}