January/February 2019^ DISCOVER^81
LEFT COLUMN: DR. ALI YAZDANI/SCIENCE SOURCE. RIGHT COLUMN, FROM TOP: VCHAL/SHUTTERSTOCK; JÖRN DUNKEL/MIT; LSPIROV/SHUTTERSTOCK
Topological Treasure-Trove
Condensed matter physicists rejoiced in July when they discovered
that thousands of common, everyday materials likely have topological
properties, meaning they can exhibit unconventional magnetic and
chemical behaviors.
Just 11 years ago, scientists identified the first three-dimensional
topological insulator, which lets electrons flow on the surface but blocks
them in its interior. That mixed ability, tied to its structure, suggests a new
way to control the behavior of electrons, and these materials could be the
key to creating exotic electronic devices. Since 2007, physicists identified
only a few dozen more topological materials.
What made July so exciting? Three independent teams scoured
databases of materials and their properties to show that all kinds of
substances — nearly a quarter of those that we already know — can
have these surprising topological properties. With a new robust catalog
in hand, physicists may be on the verge of finding just the right stuff for
tomorrow’s electronic revolution.Repulsive Attraction
Engineers from the
University of
Minnesota reported
in Nature
Communications
in May on
ruthenium’s
newly
discovered
magnetic
properties. The
element is only
the fourth in the
periodic table — after
iron, cobalt and nickel —
known to be susceptible to magnetism
at room temperature.Spaghetti
Solution
In August,
researchers
at MIT
answered
an enduring
pasta
conundrum:
Is it possible
to snap
dry spaghetti,
cleanly, into just two
pieces? Yes, but you have to twist it
approximately 270 degrees as you
bend, easier to write than do. The find
should help engineers better predict
stress failures in rods, from pillars to
nanotubes.A Criminal’s
Cancer
According to
a July paper
in Trends in
Genetics,
chemists can
now analyze the
molecular tags
attached to DNA
found at crime scenes,
potentially revealing not only
the perp, but personal health data, like
whether they have leukemia or are at
higher risk for other diseases. The tool
has sparked arguments about the ethics
of collecting and using such information.
A separate finding, in June’s ACS Central
Science, showed how traces of blood
could even reveal the criminal’s age.FURTHER AFIELD
TwistedUntwistedThe particular
shapes of
topological
materials,
shown here in a
computer model,
make them a
promising field
of research.