过渡金属氧化物-刘俊明-课件（PPT讲稿）.ppt

J. J. –– M. Liu ( M. Liu ( 刘俊明刘俊明) ) Email: Email: ******@nju. ******@nju. Group page Group page http: ./ //./ Functional transition metal oxides: effects, challenges, and opportunities 非线性光学光记录巨磁电铁电、铁磁巨磁电阻磁记录等高温超导电性强电、弱电巨介电存贮、压电巨功能氧化物材料量子新效应新材料 X. G. Li, private commun . Content 1. What we learn from chemists 2. CMR manganites 3. 4d/5d multifunctional oxides 4. Multiferroic oxides 5. Spin liquids and spin ices 6. Perspectives and challenges What we learn from chemists From Wikipeda & GC, Kentucky Transition metal oxides embedded in the periodical chart of elements 3d, 4d, & 5d transition metals What we learn from chemists 自旋电荷晶格轨道? Structure determines the interactions ? The interactions determine the orders ? Quantum theory on charges, spins, orbitals , and phonons ? Goodenough-Kanamori rules ? Tolerance factor What we learn from chemists: Goodenough-Kanamori rules ? Semi-empirical rules applied to predict ic and electronic interactions in transition metal oxides. ? Extended rules to plex transition metal oxides. M-O-M bond angle~180 o M-O-M bond angle <180 o What we learn from chemists: Tolerance factor ? A structural factor to measure the mismatch between AO layer and BO 2 layer in ABO 3 -type oxides. ? It has been extended to other transition metal oxides. )2 /()(2)( O Mn OAOB OAddrrrrf ???????f = ? ideal cubic ?f =~ ? rhombohedral & tetragonal ?f =~ ? orthorhombic ? f > ? hexagonal What we learn from chemists: strong correlation Kotliar , Phys. Today 2004 & GC, m. What we learn from chemists: multifold landscape in energy FM CO AFM OO OD CD IN ME SM SG FIM SL QP