MONTREAL,
CANADA -- Research by Young-June Kim, a physicist at
the
U.S. Department of Energy's Brookhaven National Laboratory,
may help
determine how a class of materials already used in electronic
circuits could be used in optical, or light-based, circuits,
which could replace standard electrical circuits in
telecommunications, computer networking, and other areas
of technology.
Kim¹s research
is focused on "quasi one-dimensional" cuprates,
materials that contain copper and oxygen where the
atoms are tightly linked together in straight chains
with weak lateral bonds -- like a ladder with steel
rails and paper rungs. Because the materials' properties
are mainly determined by the one-dimensional "rails,"
this structure allows scientists to simplify their
analysis by ignoring
the weak "rungs."
"One-dimensional
systems are special because we already know a lot
about their theoretical behavior," said Kim.
"Therefore, these theoretical predictions for
one dimensional systems can be tested by studying
quasi one-dimensional materials."
Kim wants to know
how the electrons in these "quasi one-dimensional"
cuprates respond to x-rays -- how the electrons behave
when they are
excited, or energized, by the light. An electron,
he said, is like a ball of negative charge surrounded
by an electric field, and also like a bar magnet with
a tiny magnetic field. Both fields affect nearby electrons,
normally at the same time. However, in Kim¹s
studies, when an electron in a quasi one-dimensional
cuprate absorbs x-ray energy, the fields separate,
allowing the electric field to
"speed up" and exert force on other electrons
before the magnetic field can reach them.
"This
response is unique to quasi one-dimensional materials,"
Kim said.
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