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wiredInUSA - December 2014
16
New observations of electron
movement in superconductors
could
accelerate
their
development.
Researcher Zhi-Xun Shen and his
team at Stanford University have
found that lattice vibrations,
known to be damaging to
superconductors, can also offer
an enhancement.
“I’ve
been
working
on
superconductors for a long time,”
Shen told Chemistry World. “This is
a new thing we can try to maybe
getmuchbetter superconductors.
It doesn’t happen very often, so
we’re very excited about it.”
Shen’s team studied films using
angle resolved photoelectron
spectroscopy
(ARPES).
The
scientists used X-rays from the
Stanford synchrotron radiation
lightsource to eject electrons
from iron selenide films, and study
their properties including energy
and angular momentum. They
found that some electrons had
less energy than expected, and
that the difference was exactly
the energy of the vibrations in
the selenium titanate substrate.
Shen explained that an individual
quantum packet of vibration – a
phonon – couples to each electron
pair, bringing them together to
achieve superconductivity. When
the electrons are ejected by
X-rays, they lose energy to excite
these phonons.
“We show unambiguously how
the substrate can play a role in
enhancing superconductivity,”
Shen stated. He added that
these phonons should help even
when electrons are paired up by
phenomena other than lattice
ripples. He now plans to attempt
to use this approach in other
materials, to discover whether
sandwiching a superconductor
between two substrates could
provide greater enhancement.
More
superconductor
research
wiredIn - Dece ber 2014