=flawed =superconductor =materials =sociology
About a year ago, there was a lot
of public interest in a supposed room-temperature superconductor called
LK-99. What I publicly
said at the time was, basically:
1. We should remember the
possibility that apparent levitation is from ferromagnetism or
paramagnetism. Iron filings can stand up on a magnet, and
pyrolytic graphite can
float over a strong magnet.
2. If we consider some known high-temperature superconductors:
- YBCO has
flat sheets of copper oxide, and superconductivity happens along those
planes. The copper in that has high positive charge density, comparable to
aluminum atoms in alumina, which gives strong bonding to the oxygen.
- H3S (paper)
has unusually strong bonds between the sulfur and hydrogen, which only form
because the atoms are pressed into each other with enough pressure to
substantially compress liquid water.
Superconductivity comes from flow
of Cooper pairs, and
the electron-phonon interaction must be stronger than random thermal
movement. LK-99 doesn't seem to have any reason to have exceptionally strong
such interactions. (Yes, I'm simplifying, you have to consider phonon
bandgaps, but the point is at least directionally correct.)
3. The
focus on "room-temperature" superconductivity is a bit silly. Even with
systems using liquid nitrogen cooling, the superconducting wires are much
more expensive than the cooling. What's really needed for superconductors to
be practical is cheaper superconducting wires, not higher-temperature ones.
At the time, I found the unusual
amount of public interest a bit bemusing. There have been various claims of
near-room-temp superconductivity, but none of them attracted as much public
attention as LK-99. A few months earlier,
Ranga Dias
published a paper claiming room-temperature superconductivity; he's now
up to
5 retractions.
What was different about LK-99?
- That was
supposedly superconducting at ambient pressure, which makes it more
practical, but also means less specialized equipment is needed to replicate
it - or claim to replicate it.
- LK-99 had a video that appealed
to people.
There were also a few social
conditions that I think were important:
1. It had been a while since
that last major excitement about fake science news. After some big story
that turns out to be wrong, people are more skeptical of science stories in
every field for a while, and then things gradually go back to a baseline.
(That's how things were after eg the "arsenic in DNA" story, which didn't
make sense either: arsenate esters aren't stable enough for DNA.) I
understand the heuristic that people applied but the way it's applied here
doesn't really make sense.
2. Misleading short videos + social media
is a combination that hadn't really been applied to bad science stories
before.
3. I think the atmosphere at the time had a lot of demand for
ammunition in a wider techno-optimist vs techno-pessimist conflict.
("Room-temperature superconductors and Boom Technology making practical
supersonic aircraft! We're so back!")
I think those overall
conditions caused the LK-99 story to be self-amplifying, because:
- Several
twitter accounts made fake videos showing "replication" of LK-99
superconductivity, because it was just good social media strategy. I think
iris_IGB is still up a lot of followers
overall. Don't hate the player, hate the game, I guess.
- Some theorists
jumped on the story by
finding "theoretical justifications" because it seemed like a net career
positive, statistically speaking.
In many cases, whether the social
status of a scientific theory is amplified or diminished over time seems to
depend more on the social environment than on whether it's true. For
example, the amyloid theory of Alzheimer's is still going, and real money is
being paid for drugs based on it that don't help people. The social
environment created a demand for evidence, and so fake evidence was produced
by people including the former president of Stanford.
For my part, a
couple of the grad students I talked with seeing data falsification going on
in their lab was a big reason for my skepticism of the university system
when I was in high school. Later on, an acquaintance tried to make an issue
out of apparent bad data and ended up being bullied by the professor to the
point of suicide. (PIs have a lot of power over their grad students' life
and career prospects.) But I wanted to warn people not to consider such
things enough of a justification to avoid getting an undergraduate degree,
with how things currently are. It's quite important to spend 16 years
studying in school to get a certification that will get an HR person you'll
never meet who spends one minute looking at your resume to not throw it out,
and it does sound like a joke when I put it like that, but it isn't.
Anyway, if there's a moral of this story, I suppose it's that, if you're
smart, you should learn enough technical details to be able to find experts
to trust on your own instead of relying on societal consensus. Or maybe it's
that you should understand the incentives of the people who determine which
stories get spread and considered credible? Actually, maybe it's that people
have biases towards believing or not believing in stories that often
outweigh the evidence? Or maybe the moral is, real events don't have a
single clear moral to them, but that's OK because you can read about as many
as you want and average out the incidental details.