For the recent Emerging leaders Special Issue published in Journal of Physics: Condensed Matter, we invited early career researchers on the forefronts of their respective fields to contribute articles. Here, we talk with Dr Ion Errea of the University of the Basque Country (UPV/EHU) about his work, motivation, and advice for young researchers. Read Ion’s work on superconductivity in metallic molecular Cmca − 4 hydrogen here.
We work mostly using first-principles calculations to predict and characterize the physical properties of materials. Our research has two main aspects. On one side, we are developing new computational methods to calculate complex properties of materials in order to broaden the possibilities that ab initio calculations offer the research community. In the last years we have developed a method, the SSCHA, that allows us to calculate vibrational properties of solids in the strongly anharmonic limit. We are currently developing this method further. On the other side, we also focus on particular applications of our methodological developments. We are mainly working on superconductivity in hydrides, systems undergoing a charge-density wave transition, thermoelectric materials, 2D materials, and so on. In many of those, the standard harmonic approximation used to characterize the vibrational properties breaks down and our new methods become crucial.
What motivated you to pursue this field of research?
I studied anharmonicity during my PhD thesis when we wanted to understand the superconducting properties of calcium under high-pressure. We realized that the harmonic approximation was breaking down and that we needed a non-perturbative method to understand what was going on. Dealing with anharmonicity in the non-perturbative regime from first-principles was, and still is, a very complicated task. However, we managed to solve the situation by applying a variational calculation. Our solution was very particular to the problem and not very transferable to other systems. After my PhD my main task has been to develop an efficient and transferable method valid to treat any strongly anharmonic system.
Where do you think the field is heading?
I would say that the field of first-principles calculations of materials’ properties is rapidly advancing. New methods are being developed to calculate more and more complex properties with an improved accuracy. At the same time, ab initio calculations are being used to predict new materials. A very recent example is the 203K high-temperature superconductivity found in hydrogen sulfide at high pressure. Before the measurement was done, ab initio calculations had predicted it. This example shows that very interesting materials will be predicted in the future using computational methods. However, I believe that if we want to discover new materials with functional properties, there is still a big need to develop first-principles methods further.
Who inspired you to become a scientist?
After I graduated I started my PhD with Aitor Bergara. When we first spoke about the possibility of working with him, he told me that it is not so important what you do in your life as long as you fully commit to it and do it with passion. He definitely transmitted that passion for science to me. I am definitely grateful to him for that. Since then, I have grown to love science more and more.
What has been the most exciting development in physics during your career?
I would say the discovery of superconductivity at 203 K in hydrogen sulfide at high-pressure, which we have helped characterize. There were many theoretical predictions that high-temperature superconductivity was possible in hydrides under high-pressure, but this experimental result only came in 2015. Now we know that high-temperature superconductivity is possible in hydrides. This field has huge room for discovery in the near future.
What advice would give to young scientists?
I still consider myself a young scientist, so I would also be happy to be given advice by more senior researchers as well. Indeed, I believe that the best advice I can give to young scientists is to choose a good supervisor. Their PhD or postdoc supervisors will be crucial in their career development not only because he/she will be their scientific reference, but because he/she will also be a personal reference. It is thus important to find someone with a very active and recognized research career, who will be committed and involved with your research, who will spend time with you, and who transmits passion for science.
On behalf of the Journal of Physics: Condensed Matter, I would like to thank Dr Errea for his time, and his groundbreaking research contributions.
Read more from our Emerging Leaders special issue here.
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Front image and image 1: copyright Ion Errea; used with permission. Not covered by CC-BY 3.0.