Room temperature polar structure and multiferroicity in BaFe2Se3

W. Zheng (1) , V. Balédent (1) , M.B. Lepetit (2, 3) , P. Retailleau (4) , E. Elslande (4) , C. Pasquier (1) , P. Auban-Senzier (1) , A. Forget (5, 6) , D. Colson (5, 6) , P. Foury-Leylekian (1)

1 LPS - Laboratoire de Physique des Solides
2 NEEL - TMC - Théorie de la Matière Condensée
3 ILL - Institut Laue-Langevin
4 ICSN - Institut de Chimie des Substances Naturelles
5 SPEC - UMR3680 - Service de physique de l'état condensé
6 LNO - Laboratoire Nano-Magnétisme et Oxydes

The understanding of the superconducting phase under pressure in the famous iron-based spin ladder BaFe2Se3 commands a perfect understanding of the structural properties. We present an accurate single crystal x-ray analysis which demonstrates that the structure admitted until now at room temperature is totally ruled out. We show that the system has a polar structure already at 300 K and is thus ferroelectric. Its structure is modified below the Néel transition and the polarization is intensified. These features unambiguously prove the multiferroic character of BaFe2Se3 as proposed theoretically. This system evidences a competition between multiferroicity and superconductivity.

Domaines: Supraconductivité [cond-mat.supr-con]; Cristallographie

W. Zheng, V. Balédent, M.B. Lepetit, P. Retailleau, E. Elslande, et al.. Room temperature polar structure and multiferroicity in BaFe2Se3. Physical Review B, 2020, 101 (2), pp.020101. ⟨10.1103/PhysRevB.101.020101⟩. ⟨hal-04275953⟩