过渡金属氧化物-刘俊明.ppt

J. –M. Liu (刘俊明)Email: ******@nju. Group page ./
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, mun.
Content
What we learn from chemists
CMR manganites
4d/5d multifunctional oxides
Multiferroic oxides
Spin liquids and spin ices
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~180o M-O-M bond angle <180o
What we learn from chemists: Tolerance factor
A structural factor to measure the mismatch between AO layer and BO2 layer in ABO3-type oxides.
It has been extended to other transition metal oxides.
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