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arXiv · 1902.10900

Polar State induced by Block-type Lattice Distortions in BaFe2Se3 with Quasi-One-Dimensional Ladder Structure

Takuya Aoyama·Satoshi Imaizumi·Takuya Togashi·Yoshifumi Sato·Kazuki Hashizume·Yusuke Nambu·Yasuyuki Hirata·Masakazu Matsubara·Kenya Ohgushi
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Abstract

Temperature dependent crystal structures of the quasi-one-dimensional ladder material BaFe2Se3 are examined. Combining the optical second harmonic generation (SHG) experiments and neutron diffraction measurements, we elucidate the crystal structure with Pmn2_1 space group in the low-temperature phase below Ts2 = 400 K, further above Neel temperature. This low-temperature phase loses the spatial inversion symmetry, where a resultant macroscopic polarization emerges along the rung direction. The transition is characterized by block-type lattice distortions with the magneto-striction mechanism. Change in the electrical resistivity and the magnetic susceptibility across the polar-nonpolar transition also suggests a modification of the electronic states reflecting the structural instability. Consistency and discrepancy with the existing theory are discussed.

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Takuya Aoyama, Satoshi Imaizumi, Takuya Togashi, Yoshifumi Sato, Kazuki Hashizume, Yusuke Nambu, Yasuyuki Hirata, Masakazu Matsubara, Kenya Ohgushi. 2019-02-28. Polar State induced by Block-type Lattice Distortions in BaFe2Se3 with Quasi-One-Dimensional Ladder Structure. https://doi.org/10.1103/physrevb.99.241109

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