Dr. Jai Maharaj
2019-07-05 22:23:56 UTC
Friday, July 5, 2019
Ferroelectric domains in a WTe2 single crystal (PFM
imaging). Credit: FLEET
In a paper released today in Science Advances, Australian
researchers describe the first observation of a native
ferroelectric metal: a native metal with bistable and
electrically switchable spontaneous polarization statesthe
hallmark of ferroelectricity. The study found coexistence
of native metallicity and ferroelectricity in bulk
crystalline tungsten ditelluride (WTe2) at room
temperature. A van-der-Waals material that is both metallic
and ferroelectric in its bulk crystalline form at room
temperature has potential for nano-electronics
The study represents the first example of a native metal
with bistable and electrically switchable spontaneous
polarization statesthe hallmark of ferroelectricity.
"We found coexistence of native metallicity and
ferroelectricity in bulk crystalline tungsten ditelluride
(WTe2) at room temperature," explains study author Dr.
"We demonstrated that the ferroelectric state is switchable
under an external electrical bias and explain the mechanism
for 'metallic ferroelectricity' in WTe2 through a
systematic study of the crystal structure, electronic
transport measurements and theoretical considerations."
"A van der Waals material that is both metallic and
ferroelectric in its bulk crystalline form at room
temperature has potential for new nano-electronics
applications," says author Dr. Feixiang Xiang.
Ferroelectricity can be considered an analogy to
ferromagnetism. A ferromagnetic material displays permanent
magnetism, and in layperson's terms, is simply, a 'magnet'
with north and south pole. Ferroelectric material likewise
displays an analogous electrical property called a
permanent electric polarisation, which originates from
electric dipoles consisting of equal, but oppositely
charged ends or poles. In ferroelectric materials, these
electric dipoles exist at the unit cell level and give rise
to a non-vanishing permanent electric dipole moment.
This spontaneous electric dipole moment can be repeatedly
transitioned between two or more equivalent states or
directions upon application of an external electric fielda
property utilised in numerous ferroelectric technologies,
for example nano-electronic computer memory, RFID cards,
medical ultrasound transducers, infrared cameras, submarine
sonar, vibration and pressure sensors, and precision
Conventionally, ferroelectricity has been observed in
materials that are insulating or semiconducting rather than
metallic, because conduction electrons in metals screen-out
the static internal fields arising from the dipole moment.
Jai Maharaj, Jyotishi