YSM Issue 96.4

Physics
FEATURE
at extremely low temperatures to express
their superconductivity.
Unfortunately, maintaining low enough
temperatures to trigger superconductivity
is incredibly expensive. Superconductors
are so useful that scientists are willing
to pay large amounts of money in
order to maintain their extremely
cold environments. But what if this
superconductivity could be triggered at
a much higher temperature—say, room
temperature? Techniques that were
previously limited by exorbitant costs
would then become widely available.
Furthermore, the scientists who uncovered
this secret would be catapulted to
international fame with their Nobel-Prizecaliber
achievement.
Many scientists have spent years
dreaming of this mission: to achieve
superconductivity at room temperature
and ambient, or standard, pressure."
On October 2020, the first instance of a
notable advancement in creating a room
temperature superconductor was reported
by a team led by Ranga Dias at the University
of Rochester, and Ashkan Salamat at the
University of Nevada. They claimed to
have observed superconductivity in a
material known as carbonaceous sulfur
hydride (CSH) at 288K (15°C). However,
this breakthrough came with a condition:
it occurred within a diamond anvil cell
under immense pressure—approximately
1.5 million times Earth's atmospheric
pressure. Additionally, there were many
concerns raised about the processing and
analysis of the data presented in the paper.
In light of this, in September 2022, the
journal Nature decided to retract the
paper. Dias and Salamat claimed again
in a second paper published in March
2023 that they had discovered a room
temperature superconductor, but this time
with lutetium hydride and nitrogen added
to the sulfur hydride. They asserted that
it had the properties of a superconductor
at temperatures of up to 294K (21°C) with
much lower pressure. However, this paper
was also retracted by Nature on November
7, 2023, following similar concerns with
their data.
Sukbae Lee and Ji-Hoon Kim, both
physicists from Seoul, South Korea, are
yet another duo of scientists who claimed
to have achieved this groundbreaking
accomplishment. In late July, they
published non-peer-reviewed pre-prints of
their work, which is common for research
scientists. At first glance, their findings
were truly groundbreaking. They had
discovered a material they named LK-99
that demonstrated all superconductive
properties under normal conditions,
ostensibly achieving the world’s first roomtemperature
superconductor.
Researchers worldwide jumped onto
this major breakthrough and tried to
replicate it. Among the physicists who
were reproducing and verifying the
experiment was Yuan Li, a condensed
matter theorist who leads a research
lab at Peking University in China. Li
collaborated with two other experimental
physicists, providing interpretations of
the measurements and observations.
“At the beginning, it looked legit. The
original authors, they do believe in what
they are saying, and they are willing
to disclose all the information to the
scientific community so that everyone can,
in principle, follow their steps and try to
verify the observation,” Li said.
Yet when Li and his team began
repeating the experiments detailed in
the original publication, their data did
not support the original claim. Because
the scientists claimed that LK-99 had
superconductor properties at room
temperature, the properties should have
been easy to replicate. Yet many physicists
and material scientists, including Li,
struggled during their replication
processes. When testing the levitation of
LK-99, Li and his team observed that LK-
99 didn’t fully repel the magnet. Instead,
one corner of LK-99 touched the magnet,
revealing that LK-99 was not levitating,
but was still experiencing ordinary
attraction to the magnet.
Furthermore, they discovered that its
resistance was not actually zero—a critical
property of superconductors. With the
evidence piling up against LK-99 being a
room temperature superconductor, Li and
his group published their findings in a
scientific journal. It turned out that LK-99,
at least at room temperature, was simply
a semiconductor with ferromagnetic
properties, or high susceptibility to
magnetization.. Along with papers from
other groups that also disproved the
original claim about LK-99, Li’s paper
helped relegate this highly-anticipated
room temperature superconductor as one
of science’s many failed attempts.
“This brings light to the high stakes
of popular science and the need for
competent ‘referees’ to overlook the
process,” Li said. Eye-catching research
fields like superconductors could
potentially revolutionize many industries,
so there is naturally a lot more funding
for these research projects, but also a lot
more pressure to produce tangible results.
More pressure for results means a greater
likelihood of falsified, or in this case,
prematurely published, research. Whether
it comes from journal peer-reviewers or
fellow scientists, regulation is needed to
prevent misinformation or misconceptions
from becoming mainstream science.
Despite the failures, Li emphasized the
importance of this research. “Although
papers were rushed, we should still thank
the researchers for their effort and bravery
to produce the research. Any information
is useful information, thus furthering the
story,” Li said.
In the quest to discover a room
temperature superconductor, we
are reminded to be transparent and
skeptical. As Carl Sagan famously
said, “Extraordinary claims require
extraordinary evidence.” It is not a sign of
failure to question extraordinary claims;
rather, it is an essential element of the
scientific process that ensures the integrity
of scientific knowledge. So, while the
journey to achieving room temperature
superconductivity may still be ongoing, the
Sagan Standard serves as a guiding light—
reminding us to think boldly, but always
demand extraordinary evidence in our
relentless pursuit of scientific excellence. ■
ART BY
KARA TAO
www.yalescientific.org
December 2023 Yale Scientific Magazine 33