Intrinsic ferromagnetic semiconductors in rhombohedral RMnO3 (R = Sc, Y, and Lu) with high critical temperature and large ferroelectric polarization. (23rd December 2020)

• Record Type: Journal Article
• Authors: Zhang, Chengfeng; Li, Zixu; Li, Guannan; Gao, Benling; Liang, Feng; Li, Zhongwen; Song, Guang
• Is Part Of: Journal of physics. Volume 33:Number 10(2021)
• Publication Date: 2020-12-23
• Subjects: high TC ferromagnetic semiconductor -- first-principles calculations -- charge ordering -- large ferroelectric polarization; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/abd1f9
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: Ferromagnetic (FM) semiconductors have been recognized as the cornerstone for next-generation highly functional spintronic devices. However, the development in practical applications of FM semiconductors is limited by their low Curie temperatures ( T C ). Here, on the basis of model analysis, we find that the FM super-exchange couplings in the d 5 − d 3 system can be significantly strengthened by reducing the virtual exchange gap ( G ex ) between occupied and empty e g orbitals. By first-principle calculations, we predict robust ferromagnetism in three rhombohedral R MnO3 ( R = Sc, Y, and Lu) compounds with the T C that is as high as ∼1510 K (YMnO3 ). The oxygen breathing motions open a band gap and create an unusual Mn 2+ /Mn 4+ charge ordering of the Mn- d electrons, which play an important role in altering the G ex . Interestingly, the rhombohedral R MnO3 compounds are also ferroelectric (FE) with a large spontaneous polarization approaching that of LiNbO3 . These results not only deepen the understandings of magnetic couplings in d 5 − d 3 system, but also provide a way to design room-temperature FM–FE multiferroics.