Marija Stojkovic

Marija Stojkovic grew up in Serbia and started her undergraduate studies at the University of Belgrade in 2013, completing both bachelor's and master's degrees at the Faculty of Physical Chemistry. After finishing, she wanted to pursue her PhD abroad to gain a different experience, change the environment and become more independent. Though she was not initially planning to come to Switzerland she found out about EPFL by chance — it is generally engineering students from her university who wind up there, rather than those who study fundamental natural sciences. She was accepted by another program, but after meeting with Prof. Nicola Marzari, head of Theory and Simulation Materials (THEOS) group, decided to join him on a project that built on the work of her master's thesis. She is now in her third year of her PhD in the THEOS group and is funded by the EPFL Excellence in Africa initiative. In her research she leverages the Koopmans functionals developed in MARVEL to study photocatalytic water splitting.  In her free time she likes to read philosophy and is interested in dramatic arts. She enjoys digging into the theory of performance, choosing an actor and following his/her work in a "nerdish" way. Her favorite artist is Serbian multi-award-winning actor, Nebojsa Glogovac, who was quoted as saying: "The world needs more compassionate and kind people rather than successful and powerful ones."

Interview by Carey Sargent, EPFL, NCCR MARVEL, February 2023

Have you always been interested in science? 

It is hard to answer. When you are a child, you are interested in a lot of things, and I would not necessarily call it science and research. It is curiosity in its purest form. But if one wants to connect it to my  present job then one can say, "yes I have always been," because I built my first lab when I was nine. This indeed happened; however, I think it was just a game. I had one magnet, a couple of iron bolts on which I could see magnetic force in action and one test tube. One of our neighbors worked in a laboratory and I remember she gave me my first test tube. It was a holy grail to me. I also remember one of the first experiments I did: my mother had a garden full of roses and I cut all the flowers because I wanted to extract something from them. It was a first chemistry experiment.  Later on in school I developed an interest in physics, but I was also interested in literature and philosophy. I am still, however when the time came for me to decide what I wanted to study and do in my life later on, science felt like a natural choice. It did not feel like a job or obligation, so I continued with that. Also, at that time, I knew that  the decision to study physical chemistry was a bit odd. People know about physics and chemistry, however, not so many know about physical chemistry, but I loved it. If there is a chance to be born again, I would study physical chemistry all over again for sure.  

During my studies I was exposed to both theory and experiments. I was introduced to simulations during the third year of my bachelor's studies through a course called "Statistical Thermodynamics". Later on, the professor of this course was my first supervisor, with whom I did my bachelor thesis. Although I learned a lot, and enjoyed my time in his lab, this research was more focused on fluids (gases and liquids).  In my final year, however, I got interested in "Solid State Physics" and it felt more like my field of study. Still, I wanted to do simulations and luckily I had the chance to meet a professor with similar interests during my master studies and that is how I found my way. That turned out to be a very good choice and we even published a paper.  

My current project is related to photocatalysis, more specifically to applying advanced quantum mechanical methods to studying the water splitting reaction by using solar energy irradiation. I can say I am still in my field between physics and chemistry. To be honest, I had tremendous luck with all of my supervisors, from the bachelor level and now up to the PhD because each one of them gave me the opportunity and freedom to be on the projects that I am really interested in  and passionate about. I tend to think that it is not so very often that students have that chance. On the other hand, it is very important to stress that students need to be more honest with themselves when they have to make a decision and choose what they really want to do. When we're young, all of us tend to be more insecure, but it is very important that people apply for a position not out of desperation but because they are really interested and care about certain scientific topics. Otherwise, is not very beneficial in the long run. A PhD is meant to be difficult and challenging, but if one is interested, there is less chance of abandoning it. Publishing papers is important, but to me it is more important to study the problem that you are really interested in and to stick to it until eventually you solve it. What really matters is to do the things you like, and to say the things you really think, no matter how lonely you can feel at moments. If we do not do what we really believe in, then sometimes we tend to think that it is everybody else's fault. However, one should take the responsibility for their own choices! 

Would you like to stay in academia? 

Without any doubt, yes! When I was in primary school, I often gave classes to my peers when they did not understand something. It was any class, not just science, and I very much enjoyed it . At that time, I thought it would be good to teach at school, but when I started university, I liked the environment more. The topics were more demanding but also more interesting for me and that has not changed so far. It may sound silly, but I also like the idea of studying and being at school forever: you get to be paid for the sake of knowledge and education itself and that is amazing. I must admit I am not a 9-5 person, I do not like mechanized work and I like the idea of working on something creative, just entertaining your thoughts. Of course, not everything goes smoothly, I myself have days when I can work up to 15 hours just because I am inspired or have  days when I read something ten times in a row because my brain is just not functioning. It is normal and it is called a learning curve. Also, when you work with students you are also learning together with them and I think you somehow tend to remain younger, at least in spirit.  

What motivates you? 

It is sort of a tough question. People have different motivations: money, fame, stability, but I tend to think that in life things generally cannot be planned and nothing usually goes according to plan. I often encounter people saying that they are going to be dedicated in the first ten years and then they can switch focus to creating a family. But it is not like that, it is something that one should be dedicated to for the rest of their life. On this point I would quote Isaac Asimov and say that education is not something that one can finish. It is really important that people understand that. To me, science is in a way like an art, it is a way of living, a lifestyle. It shows how an individual sees the world and in which way this person wants to contribute. It is not something that we get rid of after certain period — and we should not. The main drive would actually be the excitement that you get when you solve a problem. The more complex it is, the bigger the satisfaction.   

What is the aim of your research plan? 

The main goal of my project is to apply novel advanced quantum mechanical methods — more precisely Koopmans spectral functionals —  to study photocatalytic water splitting. On a large scale the project is focused on using renewable sources in order to produce hydrogen as a new fuel. However, my focus is mainly on the electronic structure of the material that can be used as a potential catalyst in this process. I am studying at the moment the properties of titanium dioxide (its polymorphs), more particularly its band structure and energy level alignment, and how that can be of relevance when it comes to solar energy harvesting and facilitating the water splitting reaction.  

What papers are you most proud of?

I am in the process of writing my first draft of my PhD at the moment, so when I finish it, I hope I will be proud of it. So far I have one paper that I am proud of: "Strain Engineering for Tuning the Photocatalytic Activity of Metal-Organic Frameworks-Theoretical Study of the UiO-66 Case" that is also related to photocatalytic water splitting, from my master studies. At the time, I studied very cool materials called metal-organic frameworks and how we could engineer their band gap and band alignment by applying strain. The paper that I am working on now has a similar concept, however the methodology is different and much more challenging especially, when one needs to apply it to a certain problem and understand how to interpret obtained results.  

Do you think women face particular challenges in science ? 

Like everyone else, yes! Maybe I do not have enough experience but I am very well aware, and I know girls my age who are confronted with people who do not take them seriously. However, I tend to observe both parts when it comes to this issue. Sometimes guys are pushed to be strong and girls to be weak and emotional. It is very important that one, no matter the gender, is aware of their own strengths and weaknesses and their own feminine and masculine sides — we all have them! A lot of things come from internal confidence and if one feels like an imposter or judged in any way, from the very beginning it can be hard to distinguish constructive criticism from frivolous comments. That said, it is important that a person chooses her or his fights in life carefully. Not everything needs our attention. Some people talk just for the sake of talking, and it can come from a rude place that has nothing to do with us but with their ignorance and their own insecurities and incompetence. At the end of the day why would anyone listen? Probably the take home message would be that we are all participating in creating a non-toxic, safe  and creative environment for all, no matter the gender. In that spirit, every one of us should be judged by our own capabilities. 

Do you have any advice for younger women interested in science? 

As I already mentioned several times, the most important thing is that we do what we truly like, no matter what the job. One can be a chef in the kitchen, or work in a cleaning service, as long as the work is done with the whole heart. Young women in science should go without fear and pursue the chosen career with the aim of becoming an expert in it. That said, I am not referring to immediate success in everything (and usually this is not the way it goes), I am  not referring to all the prizes that one can get either, but rather that one should aim to give their best every day and go home satisfied! Everything else sort of follows.