Charge-stripe order in the electronic ferroelectric LuFe2O4.
The structural features of the charge ordering states in LuFe(2)O(4) are characterized by in situ cooling transmission electron microscopy observations from 300 K down to 20 K. Two distinctive structural modulations, a major q1=(1/3,1/3,2) and a weak q2 = q1/10+(0,0,3/2), have been well determined at the temperature of approximately 20 K. Systematic analysis demonstrates that the charges at low temperatures are well crystallized in a charge-stripe phase, in which the charge-density wave behavior in a nonsinusoidal fashion results in elemental electric dipoles for ferroelectricity. It is also noted that the charge ordering and ferroelectric domains often change markedly with lowering temperatures and yield a rich variety of structural phenomena.
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
Y
Y
Zhang
H X
HX
Yang
C
C
Ma
H F
HF
Tian
J Q
JQ
Li