Nobel Lecture: Random walk to graphene*

If one wants to understand the beautiful physics of graphene, they will be spoilt for choice with so many reviews and popular science articles now available. I hope that the reader will excuse me if on this occasion I recommend my own writings (Geim and Novoselov, 2007; Geim and Kim, 2008; Geim, 2009). Instead of repeating myself here, I have chosen to describe my twisty scientific road that eventually led to the Nobel Prize. Most parts of this story are not described anywhere else, and its time line covers the period from my Ph.D. in 1987 to the moment when our 2004 paper, recognized by the Nobel Committee, was accepted for publication. The story naturally gets denser in events and explanations towards the end. Also, it provides a detailed review of pre-2004 literature and, with the benefit of hindsight, attempts to analyze why graphene has attracted so much interest. I have tried my best to make the article not only informative but also easy to read, even for nonphysicists. Zombie management. —My Ph.D. thesis was called ‘‘Investigation of mechanisms of transport relaxation in metals by a helicon resonance method. ’’ All I can say is that the stuff was as interesting at that time as it sounds to the reader today. I published five journal papers and finished the thesis in 5 years, the official duration for a Ph.D. at my institution, the Institute of Solid State Physics. Web of Science soberly reveals that the papers were cited twice, by coauthors only. The subject was dead a decade before I even started my Ph.D. However, every cloud has its silver lining and what I uniquely learned from that experience was that I should never torture research students by offering them ‘‘zombie’’ projects. After the Ph.D., I worked as a staff scientist at the Institute of Microelectronics Technology, Chernogolovka, which belongs to the Russian Academy of Sciences. The Soviet system allowed and even encouraged junior staff to choose their own line of research. After a year of poking in different directions, I separated researchwise from my former Ph.D. supervisor, Victor Petrashov, and started developing my own niche. It was an experimental system that was both new and doable, which was nearly an oxymoron, taking into account the scarce resources available at the time at Soviet research institutes. I fabricated a sandwich consisting of a thin metal film and a superconductor separated by a thin insulator. The superconductor served only to condense an external magnetic field into an array of vortices, and this highly inhomogeneous magnetic field was projected onto the film under investigation. Electron transport in such a microscopically inhomogeneous field (varying on a submicron scale) was new research territory, and I published the first experimental report on the subject (Geim, 1989), which was closely followed by an independent paper from Simon Bending et al. (1990). It was an interesting and reasonably important niche, and I continued studying the subject for the next few years, including a spell at the University of Bath in 1991 as a postdoctoral researcher working with Simon. This experience taught me an important lesson that introducing a new experimental system is generally more rewarding than trying to find new phenomena within crowded areas. Chances of success are much higher where the field is new. Of course, fantastic results one originally hopes for are unlikely to materialize, but, in the process of studying any new system, something original inevitably shows up. One man’s junk, another man’s gold. —In 1990, thanks to Vitaly Aristov, director of my institute in Chernogolovka at the time, I received a six month visiting fellowship from the British Royal Society. Laurence Eaves and Peter Main from Nottingham University kindly agreed to accept me as a visitor. Six months is a very short period for experimental work, and circumstances dictated that I could only study devices readily available in the host laboratory. Available were submicron GaAs wires left over from previous experiments, all done and dusted a few years earlier. Under the circumstances, my experience of working in the povertystricken Soviet academy was helpful. The samples that my hosts considered practically exhausted looked like a gold vein to me, and I started working 100 hours per week to exploit it. This short visit led to two Physical Review Letters of decent quality (Geim et al. (1991, 1992), and I often use this experience to tease my younger colleagues. When things do not go according to plan, and people start complaining, I provoke them by proclaiming ‘‘there is no such thing as bad samples; there are only bad postdocs/students. ’’ Search carefully and you always find something new. Of course, it is better to avoid such experiences and explore new territories but, even if one is fortunate enough to find an experimental system as new and exciting as graphene, meticulousness and perseverance allow one to progress much further. The pace of research at Nottingham was so relentless and, at the same time, so inspiring, that a return to Russia was not an option. Swimming through Soviet treacle seemed no less than wasting the rest of my life. So, at the age of 33 and with an h index of 1 (latest papers not yet published), I entered the Western job market for postdocs. During the next 4 years, I moved between different universities, from Nottingham to Copenhagen to Bath and back to Nottingham, and each move allowed me to get acquainted with yet another topic or two, significantly broadening my research horizons. The physics I studied in those years could be broadly described as mesoscopic and involved such systems and phenomena as twodimensional electron gases (2DEGs), quantum point contacts, *The 2010 Nobel Prize for Physics was shared by Andre K. Geim and K. S. Novoselov. This paper is the text of the address given in conjunction with the award. REVIEWS OF MODERN PHYSICS, VOLUME 83, JULY–SEPTEMBER 2011