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Design of Mott multiferroics via charge transfer in double perovskite oxides

发布日期:2016-10-25   浏览次数

段纯刚教授的邀请,上海纽约大学陈航晖博士来信息学院做报告,具体信息如下:

报告题目:Design of Mott multiferroics via charge transfer in double perovskite oxides
报告人:    陈航晖 (Assistant Professor, NYU Shanghai)
主持人:    段纯刚 教授

报告时间:2016年10月26日     星期三下午两点
报告地点:信息楼147

报告内容:Optimal materials to induce bulk photovoltaic effects should have a large polarization and an optical gap matching the energies of visible radiation. Ferroelectric perovskite oxides such as BaTiO3 and PbTiO3 exhibit substantial polarization and stability, but have the disadvantage of excessively large band gaps. We use both density functional theory and dynamical mean field theory calculations to design a new class of Mott multiferroics–double perovskite oxides A2VFeO6 (A=Ba, Pb, etc). While neither perovskite AVO3 nor AFeO3 is ferroelectric, in the double perovskite A2VFeO6 a ‘complete’ charge transfer from V to Fe leads to a non-bulk-like charge configuration– an empty V-d shell and a half-filled Fe-d shell, giving rise to a polarization comparable to that of ferroelectric ATiO3. Different from nonmagnetic ATiO3, the new double perovskite oxides are predicted to have an antiferromagnetic ground state and at room temperature, are paramagnetic Mott insulators with a large switchable polarization. Most importantly, the V d0 state significantly reduces the band gap of A2VFeO6 by as much as 1 eV compared to that of ATiO3, rendering the new multiferroics promising candidates to induce bulk photovoltaic effects.


报告人简介:陈航晖博士2016年回国,在上海纽约大学任教。之前他于北京大学获得学士学位,于耶鲁大学获得博士学位,并在哥伦比亚大学从事博士后的研究工作。陈航晖博士一直致力于过渡族氧化物及其界面的研究。他的理论预言先后被试验证实,并一同发表在《物理评论通讯》,《纳米快报》和《自然通讯》上。