Physicist František Herman during the Eset Science Award ceremony. (source: TASR)
This year, physicist František Herman won The Outstanding Scientist in Slovakia Under the Age of 35 category of the ESET Science Award. Herman, who works at the Department of Experimental Physics at the Faculty of Mathematics, Physics and Informatics at Comenius University Bratislava, studies superconductivity.
He earned his PhD in Bratislava and did his postdoc in Switzerland. Since he wanted to work on his own project and liked the challenge, he returned to Slovakia.
In your ESET Science Award video presentation, you said that you want to believe in a world where the importance of science does not need to be endlessly explained to people. Why did you say endlessly?
There are two reasons. The first is that globally, people who see science through its results seem to be building a kind of resistance towards it. During the Covid-19 pandemic, this manifested in denying some scientific facts. I'm tired of explaining it to someone to get vaccinated because it might save their life. Maybe it's cynical, but after a few times I found that it tires me, it doesn't help me and it gets me nowhere. It's as if I were drowning in some strange mud. The second thing is that I think it's high time to say enough.
What do you think can be done about it?
I have hope that the issue with information is akin to mushrooms in the forest. While some can kill us, others are beneficial. We have co-lived for so long that we have learned to differentiate them, realising that it is good to pass on the information that you better not put this particular mushroom in your scrambled eggs, otherwise, it will not end up well. Sure, there are cases of poisoning, but we are not debating whether it is good to take a few bites of death cap (the most poisonous of all mushrooms - Ed. note). However, the amount of information that the Internet has brought into our lives, along with how quickly it spreads, is the new forest, and we must evolve to learn to distinguish good information from bad.
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In real life, there appear to be no people who would suggest eating poisonous mushrooms, but to continue the analogy, the same cannot be said about the Internet. There are those who happily spread bad information.
Exactly. There are not just a few of them, unfortunately. Moreover, it is very difficult sometimes to distinguish between people who mean harm and those who simply make a mistake.
What's the best course of action in the meantime?
It seems reasonable to me that we should point out logical fallacies in a person's reasoning. In my opinion, it's not good to make fun of that person but to keep it factual and not get emotional.
That is to allow them to keep their humanity.
Yes. We also try to avoid emotions in scientific papers. Humans are naturally emotional beings and feelings are a subjective thing. One man's meat is another man's poison. This contributes greatly to the point of all-out fragmentation in today's world. If I came back to Your first question, I would venture to say that it would actually be better if there was no need to remind people of the importance of science endlessly. I think life would be easier. Part of science is admitting when things don't add up. The vast majority of scientists will at least admit it to themselves. Even in the field in which I do research, there are times when I'm wrong. If you're incredibly confident that you know what truth is, it's inhibiting you from coming up with something new. You are stuck with the same opinions.
In your work, you deal with condensed matter physics and, more precisely, superconductivity. First things first. What is the former about?
One direction of physics research is to go to smaller and smaller particles. Among other things, it's interesting to study what happens when there are suddenly, let's say, 10 to 23 electrons and nuclei together - I'm talking about the macroscopic scale - and how they interact. This amount brings new phenomena into play and we suddenly take into account the statistical description of particles. Solids such as metals or crystalline material have a periodically repeating lattice where the atomic nuclei basically sit in a repeating pattern, to put it simply. But since they are still small particles, we need quantum physics to describe them. So, solids are such a nice goulash of statistical physics and quantum mechanics together with Coulomb interactions (two pluses or two minuses repel each other, but plus and minus attract themselves- Ed. note). The physics of semiconductors that we commonly encounter is one of the results of condensed matter physics. From a theoretical point of view, it allows us to understand what happens in solids, understand the equations, and find out what role the charge plays. From an experimental point of view, it allows us to dope silicon so that we can make transistors, put them on a chip, and do logic processes.
Does this mean, for example, that we can improve materials?
Totally. A good example is silicon. We know what its energy structure is, that it is a metalloid and semiconductor. Based on its position in the periodic table relative to other elements, we know that if we dope it with phosphorus, we will get the same lattice, but with more electrons - an n-type semiconductor - resulting in a charge that I can do something with. If I take silicon and dope it with boron, then it will have fewer protons and electrons. The missing electrons make it a p-type semiconductor.
What can be done with such silicon?
I can arrange them alternately next to each other. If I add a battery, and a metal gate together with a layer of oxide underneath it, I create a simple metal oxide semiconductor field effective transistor, or MOSFET for short. That is the basic logic unit with which I can encode the information 0 and 1, which is basically everywhere in modern electronics. When I understand silicon, I know what to do with it in relation to other elements, how to modify the structure, how to make both n- and p-type semiconductors, etc.
Superconductivity feels a bit like nuclear fusion in that we are waiting for a breakthrough that would allow us to use it at room temperature instead of relying on large refrigerators. How is superconductivity research doing now?
It is carried out on multiple levels. One concerns the room temperature, and in this regard, we have to help ourselves get closer. We (scientists) do this by putting the samples under higher and higher pressure in a diamond anvil. For superconducting electrons, the oscillations of nuclei that sit in a periodically repeating lattice are important. Oscillations must not be overwhelmed by random movement caused by higher temperatures. For those vibrations to appear, we need a lot of pressure. For now, this is the way to do it when we want to get as close to room temperature as possible.
The research also deals with what the superconducting state does with the electromagnetic field. It turns out that we have materials that have a relatively reasonable critical temperature, on the order of tens of Kelvin, which is not that expensive to achieve. Those materials are interesting because they can induce large magnetic fields. It has applications in hospitals in MRI or as magnets used in particle accelerators. You need strong magnets to focus the particles and send them where you want them. Among these materials are ones called cuprates. Since they are brittle, they are placed on a substrate and then made into a superconducting tape that is wound on coils, and a magnetic field is then induced. Now we are looking for ways to put cuprates in strips so that they brittle as little as possible. At the same time, however, we do not quite know the details of the microscopic mechanism of how exactly superconductivity arises in them.
Another area deals with the electron spin. There is no good analogy, but imagine a small charged ball spinning around its axis. However, note that the electron is not a ball and does not spin like that. The electrons that make up the superconducting condensate are paired. Although they repel each other, the vibrations of the periodically arranged nuclei in the lattice at low temperatures can bind them so that one has spin in one direction and the other in the other direction. When we break such a pair, take the electron very far away, and look at it, and we find that it has spin up, we immediately know that the other one has spin down. I can also combine spin behaviour with other materials where spin plays a role, like ferromagnets. It is being investigated whether we can, for example, store or transport information better this way. Research into whether and for how long -in simple terms- an electromagnetic field can be enclosed in a superconducting cavity is also worth mentioning. This is interesting from the point of view of whether we can accelerate and detect particles more efficiently.
As part of superconductivity research, you constructed a model at the faculty as part of a small, two-member team that takes into account the interactions of electrons or impurities in materials. What makes this model significant?
It allows us to very simply describe the superconducting behaviour using a mathematical formula. We derived it from a microscopic theory, and when used in comparison with the experiment, it is often surprisingly consistent with what is measured. Of course, we don't claim to be the first to figure something out in this direction. In the 1970s and 1980s, a lot was discovered and theories were developed, but the way scientists approached the research had certain limits. The samples had to be either very clean, or very dirty, or the disorder in them had to be very specific, or a formula was created based on an experiment, but it was hard to find the way it resulted from the theory. And so, there were several open questions from that period. We have been able to consistently come up with an approach that nicely answers these questions one by one, plus we can also describe the behaviour of a given material in a way that is consistent with measurements. Of course, we haven't come up with the answer to every possible question related to superconductivity, even our model has limits. But having a simple description and a wide spectrum of usability is very nice in my opinion, even if it doesn't describe absolutely everything.
What was the response to your model?
We have published several articles. The first article from 2016 has a decent citation response within our field, the following ones are similar. I started during my PhD in Bratislava. When I came back to Slovakia from Switzerland, I received a SASPRO grant (a mobility programme for researchers from the Slovak Academy of Sciences, Comenius University in Bratislava and Slovak University of Technology in Bratislava - Ed. note) to work on it, which is a fantastic thing to start for people who want to come back or do research in Slovakia from abroad. We are still developing the model and looking at other directions. We also maintain communication with the outside world, it is impossible not to in science. There are days when I find myself writing more English e-mails than Slovak ones. I think molecular biologist Peter Celec said that there is no such thing as Slovak science, there is science in Slovakia. What we need to do is create the conditions for scientists to thrive and collaborate with the world.
Why did you return from Switzerland to Slovakia?
I simply feel myself at home here and for now, I am not running away from the necessary homework.
This article is supported by the ESET Foundation, whose annual ESET Science Award recognises exceptional scientists.
