"Devil's staircase"-type phase transition in NaV2O5 under high pressure.
The "devil's staircase"-type phase transition in the quarter-filled spin-ladder compound NaV2O5 has been discovered at low temperature and high pressure by synchrotron radiation x-ray diffraction. A large number of transitions are found to successively take place among higher-order commensurate phases with 2a x 2b x zc type superstructures. The observed temperature and pressure dependence of modulation wave number q(c), defined by 1/z, is well reproduced by the axial next nearest neighbor Ising model. The q(c) is suggested to reflect atomic displacements presumably coupled with charge ordering in this system.
Ohwada
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Neutron Scattering Laboratory, Institute for Solid States Physics, The University of Tokyo, 106-1 Shirakata, Tokai, 319-1106, Japan.
Fujii
Y
Y
Takesue
N
N
Isobe
M
M
Ueda
Y
Y
Nakao
H
H
Wakabayashi
Y
Y
Murakami
Y
Y
Ito
K
K
Amemiya
Y
Y
Fujihisa
H
H
Aoki
K
K
Shobu
T
T
Noda
Y
Y
Ikeda
N
N