Majorana fermions in superconductors are the subgap quasiparticle excitations that are their own antiparticles.

This thesis is devoted to an in-depth examination of the various effects of disorder in the cuprate high-temperature superconductors.

We find ourselves in an era of transition, not just towards a more computing- and data-driven society but also away from unsustainable fossil fuels as an energy source.

In this thesis we use Josephson and noise scanning tunneling microscopy for the study of conventional, unconventional (iron-based) and disordered superconductors. On the one hand, Josephson scanning tunneling microscopy allows us to directly visualize the superfluid density with high spatial resolut…

The thesis mainly contributes to the characterization of Majorana fermions as they appear in the Condensed Matter context.

In their quest for materials that conduct electricity without resistance at moderate temperatures, scientists usually work on their chemical make-up. Now Leiden physicists have come up with a radically new approach: pinching holes in a periodic pattern. Publication in SciPost.

Make more fluid: In condensed matter systems, electrons can acquire unusual properties from their interaction with the atomic lattice.

Carlo Beenakker has been appointed a Fellow of the American Association for the Advancement of Science (AAAS), the organisation behind the journal Science. Among the Fellows, he is the third Dutch person and first Leiden researcher.

Promotor: T. H. Oosterkamp

Promotor: Prof.dr. C.W.J. Beenakker

Promotor: C.W.J. Beenakker, Co-promotor: M.T. Wimmer

In unconventional high temperature superconductors, supercurrent vortices are known to spoil the Landau levels. In this thesis the emergence of Landau levels is studied in different types of superconductors: Weyl superconductors, and the Fu-Kane heterostructure.

Promotor: C.W.J. Beenakker, Co-Promotor: A.R. Akhmerov

We are a dynamic research group at the Leiden Institute of Physics. Our aim is to explore and understand quantum materials, including strange metals, high-temperature superconductors, and quantum critical electron matter.

Lecture, Tuesday Talks: Science Insights

In condensed matter systems electron-electron interactions, negligible in everyday metals, can dramatically alter the electronic behavior of the system. Examples of such altered behavior include high-temperature superconductivity and modulation of the electron density.

Promotor: C. W. J. Beenakker, Yu. V. Nazarov, Co-promotor: J. Tworzydlo

This thesis presents the results of a study on the interfaces of insulating oxides with and without the insertion of a magnetic layer.

What is the connection between materials with weak and strong gravitational interactions?

Promotores: Prof.dr. J. Zaanen & Prof.dr. K.E. Schalm

If computers work on superconducting current, they won’t consume any energy. Leiden physicists have now gained control over a new type of superconducting memory elements. Publication in Nature Communications.

In the Aarts lab we combine or structure materials, mostly in thin film form, in such a way that the hybrid has different and novel properties or functionalities.

The studies in this thesis are focused on the physical effects in the flat band materials. The results contain the discovery of strong enhancement of RKKY spin-spin interactions with specific geometric arrangement and dynamical generation of excitonic order parameter with high magnitude.

The focus of our theoretical physics research is the nature of macroscopic matter that is in one or the other way still in the grip of quantum physics.

Matthias Flór receives the KHMW Graduation Prize in Theoretical Physics for his master's thesis. His research on exotic superconductors at Leiden University and TU Delft struck a chord with the jury. The jury unanimously chose to award Flór noting that ‘he demonstrated impressive technical abilities…

Materials with strongly correlated electrons show some of the most mysterious and exotic phases of quantum matter, such as unconventional superconductivity, quantum criticality and strange metal phase.

Kaveh Lahabi's lab explores the exotic physics of quantum materials, whose underlying physics seems to have more in common with elementary particles and black holes, than ordinary metals and semiconductors.

Promotor: K.E. Schalm, Co-promotor: S.S. Lee

With the help of quantum mechanics, digital quantum hardware may be able to tackle some of the problems that are too difficult for ordinary computers. But despite these expectations and the ongoing effort of the research community, reliable quantum computers are not yet realized in a lab setting.

This is the physics summer school of Leiden University. It is part of the Leiden Institute of Physics (LION). The summer school is intended for Bachelor (BSc) students in physics. It covers topics from quantum matter and optics, to biological & soft matter physics and cosmology and theoretical physics.…

Physicist Remko Fermin from Leiden University was awarded a Rubicon grant from NWO. He will use it to study superconducting diodes that could contribute to reducing the CO2 emission of data centres.

Physicist Sense Jan van der Molen researches materials that do not exist in nature. ‘It’s fascinating to see how the properties of a material change if we manage to make it super thin.’ He will give his inaugural lecture on 21 October.

Making the most vibration-free, cryogenic scanning tunneling microscope in the world. A bold mission, but one that PhD candidate Irene Battisti successfully executed together with the Fine Mechanical Department. The new microscope might shed light on how unconventional superconductivity works. PhD Defence…

Irene Battisti is the discoverer of the year 2019. The physicist won the C.J. Kok Public Award for her research into microscopy and superconductors.

Unconventional superconductors form one of the big mysteries in physics. Among them is strontium ruthenate, which stands out as a controversial superconductor. During his PhD, Leiden physicist Kaveh Lahabi has provided new insights into the nature of superconductivity in this material, leading to a…

The behaviour of strongly correlated electron systems, such as high-temperature superconductors, defies explanation in the language of ordinary quantum theory. A seemingly unrelated area of physics, string theory, might give physicists a better understanding of the weird behaviour of these kinds of…

Physicist Kaveh Lahabi’s research on quantum materials led to the launch of a new company: QuantaMap. With his colleagues, he developed a sensor that will improve the production of quantum computer chips. ‘It turns out that what I need for my fundamental physics research is also very useful for the…

The Joan van der Waals colloquium is an ongoing bi-weekly lecture series.

Online services are stored on servers in data centres. Remko Fermin researched methods to make the memory in data centres more energy efficient.

Koen Bastiaans and his colleagues discovered a new quantum liquid unlike anything ever seen. They did it by using a technique that can be compared to listening to the sound of raindrops falling on a roof. Publication in Science 29 October.

The European Research Commission (ERC) has awarded Advanced Grants to two Leiden researchers. Joke Meijer will be researching the effect of the biological clock on our health and Carlo Beenakker will be looking for Majorana fermions in superconductors.

For the first time, physicists have visualized the ‘melting’ of electrons inside a special class of insulators. It allows electrons to move freely and turns the insulator into a metal and possibly later into a superconductor. Publication in Nature Physics.

Physicists Carlo Beenakker and Jan Aarts have been elected Fellows of the American Physical Society. Carlo Beenakker: 'People acknowledge your contribution, that is just very good to hear.'

An overview of awards and prizes granted to our staff and students in 2019, as well as special appointments and royal distinctions.

Majorana particles have been getting bad publicity: a claimed discovery in ultracold nanowires had to be retracted. Now Leiden physicists open up a new door to detecting Majoranas in a different experimental system, the Fu-Kane heterostructure, they announce in Physical Review Letters.

Stack two layers of graphene, twisted at slightly different angles to each other, and the material spontaneously becomes a superconductor. Science still can't explain how something so magical can happen, but physicists use special equipment to reveal what is taking place under the surface.

Scientists at TU Delft and Leiden University have observed supercurrents in graphene that bounce back and forth between the edges of the graphene without scattering along the way.

Knots come in all shapes and sizes: mariners and scouts can vouch for this. Sjabbo Schaveling will obtain his PhD on 1 September for a mathematical method to distinguish between all these knots. ‘I flatten them to a pretzel.’

From educational adventures in the tropics, students building software for real customers, to bacteria that degrade plastics. Scroll through our highlights on educational innovation and the achievements of our students.

Physicist Milan Allan will build an instrument that will bring superconductivity research further. He has been awarded an ERC Consolidator Grant of 2 million euros over the next five years. With his PairNoise programme he aims to detect paired electrons as they occur just above the temperature at which…