Hello, and welcome to the Physics World weekly
podcast.
I'm Hamish Johnston.
I'm very pleased to announce that the 2025
Physics World breakthrough of the year award
goes to Gong Yuzhang
and colleagues
at the Institute of Physics of the Chinese
Academy of Sciences.
And they've won for producing the first
two d sheets of metal.
Coming up, I'm in conversation
with Gong Yu, who explains why his team
worked
tirelessly
to create two d versions of several different
metals,
and how these new materials could boost our
understanding of condensed matter physics
and lead to the development of new technologies.
I'm also joined in this episode by my
colleague, Matin Durrani,
to talk about what will be hot in
physics
in 2026.
But first, a message
from reports on progress in physics,
which
supports the Physics World
Breakthrough of the Year Award.
Celebrating the most significant
advances
across the physical sciences,
this award
highlights discoveries
that reshape
our understanding
of the universe
and inspire
future innovation.
Reports on Progress in Physics
is the leading journal for authoritative
research,
connecting researchers worldwide
with cutting edge insights
across every field of physics.
From quantum technologies to astrophysics,
it provides
the depth and clarity
that drive
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Search
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science today.
One of the hottest topics in physics over
the past two decades
is the study of two d materials
such as graphene,
which itself is a sheet of carbon just
one atom thick.
While researchers have discovered
a plethora
of fascinating
and potentially useful
phenomena
in two d materials,
physicists
had not been able to create and study
two d versions
of metals.
But now,
Gong Yuzhong
and colleagues
have found a way forward.
He joins me down the line from Beijing
to talk about his group's research.
Hi, Gong Yu. Welcome to the podcast.
Hi, Hamish.
Nice to meet you.
And and congratulations
to you and your team for, winning this
year's
Physics World breakthrough of the year.
Thank you very much.
So so I'd like to start, with the
basics, with the motivation
for your research.
Why why are you interested in creating
two d metals? Why why are they, you
know, such a fascinating system?
Okay.
So,
this question actually can be divided
into two questions.
The first one is why we are interested
in,
two d materials, and the second is,
why we are interested in, metals.
So the first
question is,
because,
right now, everybody knows,
graphene. Right?
So graphene is a well known two d
materials. It's discovered
in 2004,
from,
Manchester,
University.
So the two d material has many fascinating
properties.
So related to,
their,
low demand,
low dimension
analogy.
So when you,
shrink,
a bulk material
to, two dimensions,
this this this material is is very, very
faint. It's atomically thin. So such same materials
have,
so in most cases, it has very different,
properties,
compared to their buck,
like a like a graphite,
versus,
graphene. So graphene is very different,
to to to graphite. Right? So this is
a one, one one,
motivation. So we are,
are going to pursue,
like, new two two d materials.
So
the second one is why why metals. Right?
So, metals are are are very common in
our in our daily life. Right? You can
see it everywhere, and we use it every
day. Right? So so metals,
if you look at the theoretical,
table,
you will find, like, over like, around 80%
of elements are metals. This is and metals
are are are are, it can behave very
differently, like, from
metals can be magnetic.
Metals can be,
can be silver conducting,
and, metals,
so can be used for for, you know,
for many, many,
cases.
So, like,
so this huge amount of,
of of of choices in the
periodical table. So we we want to do
it, like,
in two d forms of metals. But,
like,
spuriously,
these metals, actually,
they cannot be made into the key two
d forms. The the the this is our
motivation.
And and you mentioned that it it is
very difficult to make metals
into,
into two d materials.
Can can you explain why? Does it have
to do with how the
atoms in a metal bond
differently
to, let's say, carbon
atoms. Is is is that the main problem
that they just don't want to
only bond in in two directions? You've you've
got the third direction as well.
Exactly.
So,
like in graphene, carbon atoms are are bonded
in,
in, in a form of covalent bonds. So
these bonds are very strong.
And, also these bonds are very anisotropic. So,
this is one reason,
like, we can,
use, the exfoliation method to create two d
materials for many two d materials, like graphene,
like a black phosphorus, like like,
like, a monolith sulfide,
like many many many other materials.
So, but if you look at the metals,
so most metals are
are are isotropic.
So so
if
the atoms are arranged,
like, if you look at the lattice so
if if you regard
one atom as a man, so if you
look, like, all around a few, so you
will see up and down, left and right,
back and forth. Like, you see
yeah. You are surrounded by by many items,
but these items are are the same,
just as the same to you that that,
so that means this this materials,
you know, the lattice is is very isotropic.
So you cannot use,
like, a mechanical,
exfoliation
method
to to create, like, a two d form
of metals.
So this is the one, one one,
difficulty.
And, I mean, that's you know, when when
we were looking over,
you know, all the sort of work that
that's been done in physics this year,
you know, I think, you you know, the
the the fact that you've managed to overcome
that was the thing that really stood out.
And, you know, it's why we we chose,
your work as our breakthrough of the year.
You know, we were scratching our heads thinking,
how on earth,
you know, have they managed to to get
a a metal to to to create,
a a two d structure? So how did
you do it? How did you overcome
this
urge for metals to bond in all three
dimensions,
to to create a two d metal?
Yeah. So, in principle,
metals cannot have a stable two d structure.
Like,
if you use a, like, a freestanding
a two d form of metals,
this structure is totally,
not stable.
So, it is it it should not be
existed, in nature.
This is the the the the also violation
of a of a common sense. Like, so
so we we have,
so we developed we have developed our, a
a a a process. We called it one
of our squeezing.
So
so the idea is very simple.
Like, so,
so if you like,
you just imagine
a metal like
a a a kind of like a model
or something. Like, it's very soft. So if
you squeeze it, you squeeze it, you can
make it thinner and thinner. So the problem
is if you can squeeze it
into,
like, just a,
one atom sick, like,
to a physical limit. So that's that that
is,
the most important,
thing.
So we have,
this the thing is, like, if you want
to, like, squeeze it
squeeze, like, press
the metal,
into,
the, the two d image.
So we need,
we need to
use, like, a the the top and the
bottom surface must be atomically
flat. So, otherwise, you cannot create, like, a
large area of of two b two d
crystals.
So the second thing is you have to
use,
like, a quite high pressure
and,
and last quite a long time
to make these metals, like, to to, like,
rearrange,
like,
at this confined surf confined space. Like, it's
confined by the two surfaces of these atomic
is most surfaces.
And,
and,
to make it like to to rearrange in
this confined
space to form a two d metal, a
lattice.
And and so you
you were able to to to do this
with several
metals.
Yeah.
I think five of them. Did you,
were they I mean, once you managed to
get them,
you know, sort of into a two d
structure,
did they do they still behave like metals,
you know, in the sense that we would
think of metals as being
good conductors
of electricity, for example,
or did their properties
change dramatically?
Did they become semiconductors or insulators? Or Yeah.
You know, what Yeah. What exactly happened?
Yeah. That's
what we are we are studying right now,
actually. So
we we found that, like, for a very
simple,
metal like bismuth. Like, so so the bismuth,
if you make it to two d. But,
actually, you have
it will have in principle, it will have
different
atomic structures.
Like, it have different phases.
And these different phases give you totally different
properties.
So some of them are are just, metallic,
very, very, very
electronically,
very conductive.
And, the others are are even, semiconductor, but
the gap is is quite small.
And, also, the we have we have,
we have developed this pro
approach approach,
for,
right now, we have,
reported
five
single element,
single element metals,
like but, actually, we can do more,
like, because of the the the the like,
88,
kind of metals in the in in the
theoretical table.
But right now, it's just five. So we
still over, like, eighties
18 metal, like, a single atom metals to,
to do, like,
later. And, also, if you consider
the metals actually,
it it
it it have other forms, like binary
alloys, like like like
like bismuths and,
and, and, and, something else,
like and, also, you have much more, complex
system, like of like, for example, like, five
different,
metals. You can mix it together and,
and make it in two d form. I
think this kind of works are very interesting
in the future and we are doing that.
And have you I mean, in terms of
yeah. I I know it's sort of early
days in terms of studying the properties of
these two d metals. But are there,
I mean, do you have any experimental evidence,
or maybe there's theoretical predictions
that some two d metals could have very
useful
electronic properties,
you know, for, I don't know, creating
computer chips or sensors or quantum devices?
You
know, is there some technological relevance here?
Sure. Sure.
I think there are
plenty of,
possibilities
in the future to do such studies. Like,
you know, like,
for example, just as you mentioned, like, for
computer chips. So if, like, because right now,
the CPU chips, like,
so the basic elements are, transistors.
So when the when the transistors are getting,
like, smaller and smaller,
like, like, so we, like,
because,
the Moore's law is still going. Right?
So
so we want to make such a fabricate,
such transistor, such devices to be, like, even
smaller. Like, when you, like,
shrink shrink reduce
the dimension of of of the size or
the size of the device to to be
very, very small, like, at at a a
nanos
at nanometer scale. So you you view we
we view
face this
serious problems,
like, about about this dimensional,
reduction.
For example, so every transistor use metal contacts.
So when the metal wears
are reducing, like, around, like, 10 nanometer
or or something around, like,
it will be
less connective, and it will be face, like,
variation problem.
So if we we can replace such a
connecting wires
to,
like, a two d metals,
it will be much better.
I see. Yeah. Another thing is, yeah, another
thing is, like,
I I I give you another example. Like,
like,
we know, like, like,
like, Aaron Nickel or something like that.
It's magnetic.
So but, but the thing is, if you
can make it, like, a a a single
atomic layer of of of Aaron or or
nickel or cobalt,
Like, this kind of thing can give you,
quite,
quite, promising,
properties,
because,
in theory, we have some calculations,
previously.
Like, if you make such kind of thing,
you can use it for some, like, like,
like, quantum hall effect.
You can make some useful devices,
like, in the future.
And you mentioned that, you're interested in your
lab at at exploring
other metals, you know, whether you can make
two d versions of other metals. Are some
metals easier
to make in two d than others?
Is that what you've found, or is that
what you expect?
Sure.
This is absolutely
true. Like,
because we we we have, we have report
five. Right? Five type of metals. That kind
of metals are actually are easier are easier
to make, like, in two d forms.
But, for some,
some other metals, like, especially the the high
melting point metals,
is is where it's it's quite difficult. It's
more difficult to, to make,
because this is limited by,
by by the experimental
setup,
because in that, you you need to,
add a high pressure.
At the same time, you you you you,
you thought
a
high high temperature. Right? The temperature is higher
to make your
make these environments,
like, more difficult.
I see. Okay. Well, it sounds like you've
got lots of,
lots of potential work for you and your
team
in the future.
So thanks thanks so much for coming on
the podcast. And, again, congratulations
for,
for being the, recipients of the Physics World
breakthrough of the year for 2025,
you and your team.
And, yeah, here at Physics World, we wish
you all the best.
Thank you.
Thank you, Hamish. Thank you. See you
later.
That was Gong Yuzhang
at the Institute of Physics of the Chinese
Academy of Sciences,
who led the team that has won the
2025
Physics World breakthrough of the year award for
their pioneering work on two d metals.
And there's much more about the Physics World
breakthrough of the year and the nine
runners up on the website.
As this year is drawing to an end,
here at Physics World, we're busy planning for
2026.
Joining me to chat about what will be
hot in physics
in the coming year is Matin Durrani,
editor in chief
of Physics World.
Hi, Matin.
Hello, Hamish.
So,
what's going to be hot in physics in
2026?
Do you have any pics? Have you got
your crystal ball out yet?
Well, you're right. I what I always used
to do is I'd get my imaginary
crystal ball out and try and predict what's
gonna happen in physics. But you know what
it's like, Hamish. It's so difficult to know
what's gonna happen in physics because,
you know, if we knew what was gonna
happen, we wouldn't bother doing physics. We wouldn't
get out of bed, would we?
I mean, there were only some things that
you can always guarantee, which are things like,
specific space missions launching or a particle collider
opening or a light source. And those are
sort of the big science projects, which have
big timetables and, you know, big plan. Those
are the kind of things that you can
know about for sure.
But it's a really thankless task. So, basically,
Hamish, to answer your question, what's gonna happen
next year? I don't know. However, we've got
a couple of things lined up on Physics
World, which,
these, online panel discussions called, Physics World Live.
And I guess we've got three coming up,
which in a sense is our take on
what we think of the, the big things
in physics happening right now.
And these I mean, I have to say
these are very timely topics.
One of them is quantum metrology,
and anything quantum is very hot. I mean,
you're you're pretty well guaranteed that anything quantum
will be hot and exciting in 2026.
Another one is on fusion energy,
and it seems like the momentum is is
growing, isn't it, for fusion fusion energy? Lots
of small and medium sized companies coming in
with,
novel technologies that they hope will sort of
crack,
crack what has been a very difficult problem
getting fusion energy going.
Medical physics, again, you know, applying physics to
medicine is a very, very hot topic. So
what what what are these physics world live
events? And so what, you know, what what
why are we covering these topics?
Well, we've been doing this for a few
years now, Hamish. So these are online panel
discussions
about,
particular hot topics in physics.
So anybody can register and and and watch
them. So, yeah, the first one, which you're
actually organizing, Hamish, so I hope you know
what this is about. It's about quantum metrology.
So the idea of,
ensuring it's ways of ensuring companies and academics
can sort of test and validate and commercialize
new quantum tech. And we know that, you
know, it's been the International Year of Quantum
Science Technology, which, by the way, that is
one thing that's happening next year. It draws
to a close with a closing ceremony in
Ghana, so that's something that's happening.
And we know that there's a it's a
burgeoning industry, and you need the metrologists
to come in and sort of validate
these technologies and make sure that everybody's operating
to the same standards and principles. And you
can sort of you could compare different
pieces of kits, and it's really important that
you have that in place so that the
industry as a whole can
can make progress. So I think quantum metrology
is a really important area. So, well, we're
looking forward to doing that one. Oh, definitely.
I I was I was very lucky. I
went to a a conference or a meeting.
I suppose possibly it's better to describe it
as on quantum
metrology
at the National Physical Laboratory
in The UK,
which is the, you know, the the institute
institution in The UK that looks after things
like standards and develops new technologies for measuring
current, and, you know, all those sorts of
things. And it's always a real pleasure to
go to NPL. The physicists who work there
are fantastic.
They, you know, they work on some really
interesting projects, and they're always really happy to
chat.
And, yeah, definitely, quantum metrology
is, is a hot topic there. And it's
interesting that
one of the things that I suppose I
never really thought of before I went to
the conference was this distinction
about
using
quantum
to make better
metrology,
versus
developing
metrology
to make better quantum technologies.
And I suppose a classic example of the
former
is,
an atomic clock, where you're using the, you
know, the quantum properties of atoms and of
lasers,
or masers
to,
to to to make a a much better
time standard. And that's a great example of
using quantum
for metrology.
On the other hand,
when you're developing new quantum technologies,
you need
standards,
to,
I suppose work out if those quantum technologies
are are good enough for doing what you
what you want them to do. So for
example,
a quantum computer is based on qubits, and
you need to decide whether these qubits,
remain quantum for long enough
to do your,
your calculation
on the quantum computer. So, you know, you
need to
define standards,
metrology standards for how good a qubit is.
So, you know, there's two ways of looking
at quantum metrology, you know, harnessing the power
of quantum mechanics to make better metrology,
and then actually developing
metrology for new quantum technologies. So, yeah, it's
doubly
exciting, I think. So, yeah, stay tuned for
that.
Yeah. Because it's amazing things like entanglement being
used for practical purposes. You know, I was
at the
Institute of Physics
event at the Royal Institution in London last
month in November, and there was a representative
from the company,
Digistain that makes entangled cam, which is this
piece of equipment using entangled photons for medical
physics purposes.
And, you know, it's incredible to think that
that's happening and that you well, you know,
if there's other companies in the area, how
do you make sure that they're all working
to the same standard and that you could
compare one entangled camera with another? You know,
these are kind of questions that you need
metrology for. You need that system in place.
Like with the kilogram or the second, you
need those systems in place so that we're
all operating to the same,
principles. Oh, definitely. It's a big big deal,
and it's, you know, just that area that
physicists make, you know, contributions to.
And yeah. I mean, I I suppose now,
you know, entanglement is not seen as a
sort of a weird thing. It's seen as
a resource. I mean, that's how how people
describe it these days. Entanglement is a resource
for quantum computing.
And, so, yeah, how do you measure it?
Exactly.
So, yeah, I think I think quantum metrology,
all different flavors of it, will be very
exciting next year. Good. Because you you're organizing
that event.
I'm glad you're enthused about that. Well, you
know, I've I've I've at least I've spoken
to lots of interesting people at NPL about
it. So, yeah, I'm sure it'll be, it'll
be a a great success.
And, I mean, I suppose fusion is the
same way, isn't it, in the sense that,
there's a lot of interest in fusion energy,
a lot of,
companies that are springing up with their own
sort of takes on how to
extract energy from the fusion of
hydrogen
nuclei.
So can you tell us a bit more
about that PW Live?
Well, I mean, if you think of fusion,
you tend to associate it with the big
project like Eat Well, ITER in Southern France.
That's a huge,
machine being built at the moment. But there
are a lot of private companies involved in
this area at the moment. So not last
week, I was at the Institute of Physics
business awards
in London at the Houses of Parliament, and
there was somebody from Tokamak Energy
who, they won one of the business awards.
And she was their chief
technology officer and used to work at Rolls
Royce Aerospace in Derby.
And,
you know, she said to me, and I
didn't quite realize this, they have 300
members of staff there including
a 120 people with PhDs. So, you know,
these are, you know, big companies, serious companies
with a lot of effort being put into,
you know, harnessing fusion
as an energy source
and building the magnets and so on and
coming up with designs for how it would
work. So, yeah, that that's, you know, that's
gonna be in the,
towards the end of next year when we
have that Physics World Live. So, yeah, looking
forward to that one. Yeah. That'll be interesting.
I mean, I have to say I'm a,
you know, sort of a slight skeptic
when it comes to fusion.
And, I I often wonder that,
you know, the reason why we have all
these small and medium
sized companies
is that it's turning out to be incredibly
expensive
to build a large
fusion facility.
And we sort of think, well,
maybe that's the problem.
It's that we're trying to build a large
one. Maybe we can build a small one.
But I don't I don't know. Is that
backed by physics and engineering? Or is it
just, well, we tried it one way, and
it's taking a long time.
And, you know, we haven't got the results
that we've wanted, so we just try it
another way. I mean, that's fair enough. I
suppose that's a a fairer way to innovate.
But, I mean, there's that notion of there's
that notion that we covered in physics world
this year of unobtanium.
The idea that you set yourself a challenge
knowing it may might not be possible. Yeah.
But, you know, trying to get there
as a target is a useful exercise because
other good things might happen along the way.
And, you know, you hope you achieve it
and if you but if you don't, you
may come up with other breakthroughs or other
developments that are also useful. So unobtanium, I
think, is quite a nice way of putting
it.
Again, the other idea is vaporware, the idea
that something sort of so ethereal that you
you may it may never even happen, but,
you know, still worth pursuing. So, yeah, fusion
is,
you know, exciting times at the moment.
So medical physics, I mean, that's a a
very broad,
field.
Has that one been narrowed down,
that PW Live? Or Well, we got a
couple of speakers lined up for this one,
which is,
we're running it in July to celebrate the
seventieth anniversary of the journal
Physics in Medicine and Biology, which IOP Publishing
publishes,
on behalf of the Institute of Physics
and Engineering in Medicine, IPEN.
So it's celebrating its seventieth anniversary. So we've
got the current editor in chief and two
former editors editors in chief lined up to
speak about the role of medical physics in,
medicine and biology and how that field has
evolved over the last seventy years. So that's
definitely one to look forward to. And, yeah,
a lot lots going on in that area
as well as we all know,
all sorts of different things. Oh, interesting. Yeah.
I just I I did a podcast interview
today, earlier today.
I've, the microphones have been out all day
today. It's been very busy
with,
someone called,
Luke Cox at a company called Impulsonics.
And they're using,
ultrasound,
in a medical application that,
you know, it's nothing
to do with ultrasound imaging.
It's using the effect of ultra ultrasound on
cells
to, you know, to
encourage processes that could ultimately be used for
things like personalized medicine.
So, yeah, I mean, things are very exciting
in medical physics. Yeah. Well, we saw the,
physics well, our own top 10 breakthroughs for
2025
that included one of the breakthroughs was on
proton arc therapy. And, of course, proton therapy,
you know, twenty years ago is brand new,
and that's being refined
further and further. So, yeah, lots lots going
on in that field. So, yeah, medical physics
will be the,
physics worldwide in July.
And there's one more thing, I think that
we can preview, Matin, and that is that
our colleague,
Margaret Harris, is going to the Global Physics
Summit, which is the big,
APS shindig.
That's in March,
in Boulder, Colorado.
And she'll be doing a a live event
there. Is that right? That's right. So Margaret
and will be, hosting a Physics Worldwide at
the Global Physics Summit, for people who are
attending that in Denver and Colorado,
which is funny because I went there in
2020
just when the pandemic struck. And I was
there with lots of other people, and the
whole meeting was canceled.
And that was a very strange experience. So
we spent a week, six well, it'd be
six years ago now,
you know, in this cavernous
auditorium and conference hall with nothing going on,
and all the companies were sort of packing
their exhibits away. So it's back in Denver
in, in in the spring. So, yeah, that
that's what Margaret will be doing about careers
in physics. And, of course, we know that,
you know, physics degree can open all sorts
of doors, but often there are so many
doors that it can open that people aren't
aware of all the opportunities that are available.
So we'll be looking at some of the
options that you can do,
with a degree in physics. So that's another
thing to keep an eye out for next
year. Sounds good. I've I think I've been
to a few APS conferences in Denver. And,
you know, I have to say the best
thing about going to a conference in Denver
is that it's very close to Boulder, Colorado,
which is the headquarters of, an well, not
the headquarters, but one of the big,
sort of outposts of NIST,
the, American Standards Institute,
which, like NBL, is a fantastic place to
visit. Lots of amazing physicists there doing some
incredible work. So, who knows? Maybe Margaret will,
be able to visit the folks at NIST
as well.
Yeah. That's where I mean, I know in
in Boulder, they do a lot of on
the the atomic clock work is done there.
So that's,
great.
The other thing to mention, Hamish, that I
should also add in is that our colleagues
at the Institute of Physics in London are
doing,
more of their impact projects.
These are the sort of in-depth reports looking
at important tech technology areas. So they're doing
more work on,
artificial
intelligence,
and they're also starting a new impact project
on medical physics, which ties in with what
we were saying about medical physics being important.
So those three areas, AI, metamaterials, and medical
physics, the Institute of Physics will be looking
at with their impact reports, which are we've
done ones,
previously on quantum physics and the green economy.
So those are sort of three areas that
are, you know, also hot topics.
Like I say with physics, I said to
you a few minutes ago, Amish, you never
can quite predict exactly what will happen, and
so I'm not going to. But I think
these areas that I've talked about, we've talked
about, kinda give a sense of, you know,
where the where the hot topics are in
in physics right now as far as we're
concerned.
So, yeah, lots to look forward to, in
2026.
I'm afraid that's all the time we have
for this episode, which is supported by reports
on progress in physics.
Thanks to Gong Yoo Zhong and Matin Dharani
for joining me today,
and a special thanks to our producer,
Fred Iles.