It’s sitting somewhere on the bookshelf: “Solid State Physics”, a standard work by Ashcroft and Mermin. Ingrid Mertig, a professor of theoretical physics, looks unsure when we ask about it and smiles somewhat incredulously. She desperately wants to know where the tip came from. Of course she has the book at her fingertips, and she also knows what we’re getting at. But the book remains on the shelf.

Fine, then let’s start over on a different note by reading off an unbelievably long list of her previous roles: member of the Science Council, expert at the German Research Foundation, head of the working group “Quantum Theory of the Solid State” at the University of Halle, spokesperson for the collaborative research centre “Functionality of Oxidic Interfaces” and for the state’s key area of research, “Nanostructured Materials”, Max Planck fellow, member of the “International Union of Pure and Applied Physics (IUPAP)”, member of the Academic Senate - the list goes on. That should be enough to allow us to talk at length about her success, shouldn’t it?

Ingrid Mertig looks unimpressed. Did we miss the mark? “No, success to me means something completely different,” she explains. “Success means having scientific insight.” She explains that that’s the only thing that makes her happy. She looks back with pleasure on her research work on giant magnetoresistance, the so-called GMR effect. This discovery, made by two solid state physicists, Peter Grünberg from the Jülich Research Centre, and Albert Fert from Paris-Sud University, led to the inception of a new area of research – spintronics. The GMR effect led to the development of computer hard drives with very high storage densities. Grünberg and Fert were awarded the Nobel Prize for Physics for this discovery. She has stayed in contact with the two basic researchers. “Once I understood this effect, it was a real joy,” raves Mertig. It’s no secret: as a member of this community she also knew British experimental physicist Stuart Parkin, who came to Halle’s university in 2014 under a lot of media attention. Mertig was able to acquire an Alexander von Humboldt Professorship for him.

As a young pupil she showed a keen interest in the natural sciences – for every field, it should be noted. “I could have just as easily studied chemistry or biology,” recalls Mertig, who began studying physics at the Technical University of Dresden in 1974. “Maybe because physics posed the greater challenge for me.” After graduating in 1979 she went on to get her doctorate in 1982, afterwards experiencing an exciting postdoc period. She and her husband, also a physicist, went to the Joint Institute for Nuclear Research in Dubna, Russia for five years. Here she met many scientific colleagues, set up networks and compared current states of research.

In 1990 she began travelling the world as a guest lecturer, with stints in Paris, New York and Nagoya (Japan). After her time as a Heisenberg fellow, she received an offer from Halle in 2000 and became the chair of “Quantum Theory of the Solid State” in 2001. She and former dean, Heinrich Graener, devised a plan to develop the Institute of Physics over the next ten years. Consequential appointments helped build up the key research area of nanostructured materials. One element of this is the study of ferroelectric and magnetic oxides with innovative properties which are an important research component of CRC 762. Here fundamental principles are developed for potential technical applications, including completely new approaches for storage technology.

Over the years, Ingrid Mertig has gained an international reputation as a high-calibre researcher, having published more than 200 articles. In 2011 she was appointed to the Science Council. Mertig is at home when it comes to managing science. She is well-versed and is a good organiser, leader and director. She has undertaken many assignments for the German Research Foundation – as an expert scientist and as a member of the nominating committee for the Leibniz Prize. Mertig is an analyst through and through. She can discriminate between what is relevant and what is irrelevant. She is able to condense a flood of information and quickly gets to the heart of an issue. And she is able to build bridges and win over people. Maybe that is what makes her so successful in steering and heading up large research collaborations like CRC 762, which has 27 project leaders. Oh, and another thing: she’s very meticulous. Endless discussions that are lacking in expertise are not her cup of tea. Ingrid Mertig likes numbers, data and facts, and attempts to bring structure to debates with the aid of her notes, which she takes everywhere in a spiral-bound notebook.

She is also highly esteemed by her students, something which her colleague, Professor Wolf Widdra, reveals during a quiet moment. Her lecturers are popular in a subject that is often not that straightforward. Teaching is Mertig’s passion. It makes her come alive and fills her with enthusiasm. “I really love teaching. My aim is to familiarise everyone with the beauty of theoretical physics. At the same time it’s a privilege for me to see how young people develop and live up to their potential.” Many of her students are now established scientists. Mertig’s first doctoral student in Halle was Christian Heiliger, who now teaches as a professor at Justus Liebig University in Giessen. Then there is Martin Gradhand, who is following his calling as a lecturer at the University of Bristol (England).

In the 1980s, Ingrid Mertig began to intensively study fermi surfaces. These surfaces, she says, are the calling cards of metals. “At some point, when computers were powerful enough, I came up with the idea of writing a programme that would enable all of these fermi surfaces to be visualised.” And this is where the book “Solid State Physics” re-enters the story. Ingrid Mertig retrieves it from the bookshelf. Back then the visualised fermi surfaces were an exciting novelty which attracted the attention of the authors. The fermi surface of nickel made it onto the cover of a book that physics students around the world bury their noses into.