How to separately flip the spin and angular momenta of a single atom


In a publication in njp Quantum Materials, Rasa Rejali demonstrates the ability to make independent rotations of the spin and angular momenta of a single iron atom. This was made possible by positioning that atom on a highly symmetric binding site of a copper-nitride surface. In theory, this should make it possible to store two (quantum) bits of information on one atom. But for now we focus on the more fundamental question how a single tunnelling electron can completely invert the orbital angular momentum without violating conservation of angular momentum. This apparent contradiction can be explained in the framework of the Einstein-de Haas effect.

Inaugural lecture Prof. dr. A. F. Otte


On Wednesday September 11th, Sander Otte gave his inaugural lecture as Antoni van Leeuwenhoek Professor. During his 30-minutes public lecture, he took his audience to the border between classical physics and quantum physics. Highlight of the lecture was a live demonstration of an experiment on structures of actual magnetic atoms, positioned in such a way as to visualize the existence of this border.

You can watch the lecture, which was in Dutch, here.

NWO Vici grant for Sander Otte


Sander Otte has been awarded a Vici career grant by Netherlands science organisation NWO. In the coming five years, we will use this funding to setup a research direction where we use STM-based electron spin resonance to study the dynamic behaviour of collective excitations in atomic spin chains. More information can be found here.

Publication in Surface Science


In our newest publication in Surface Science, we present controlled growth of c(2  ×  2)N islands on the (100) surface of Cu3Au, which can be used as an insulating surface template for manipulation of magnetic adatoms. Compared to the commonly used Cu(100)/c(2  ×  2)N surface, where island sizes do not exceed several nanometers due to strain limitation, the current system provides better lattice matching between metal and adsorption layer, allowing larger unstrained islands to be formed. We show that we can achieve island sizes ranging from tens to hundreds of nanometers, increasing the potential building area by a factor 100. Initial manipulation attempts show no observable difference in adatom behaviour, either in manipulation or spectroscopy.

STM topography of a single nitride island on Cu3Au with a diameter of 40 nm. On the island, two manipulated structures composed of Fe atoms are visible.


Atomic arrays paper in SciPost Physics


Have a look at our latest paper, published in SciPost Physics. Here we report on the investigation of atomic arrays of various shapes and sizes, built out of individual atomic vacancies. This way, we construct small artificial two-dimensional materials which show the beginnings of band formation.

SciPost is a recently initiated publication portal that is fully open-access. In contrast to most other journals, it features ‘peer-witnessed’ review. This means that the refereeing process is completely open and that anyone – so not just the invited referees – can contribute comments, resulting in a fair and transparent review process.

STM topography and corresponding local electron tunneling spectroscopy on various arrays built from atomic vacancies in the CuCl/Cu(100) surface. It can be observed that for denser lattices, the onset of the conduction band – originally at 3.5 eV – is shifted further downward.

Lecture at ‘Diligentia’


On April 3rd, Sander Otte gave a lecture at the Koninklijke Maatschappij voor Natuurkunde ‘Diligentia’ in the Diligentia Theatre in The Hague. This one hour lecture, in Dutch, provides an overview of the field and discusses several concepts on a level that is accessible to first-year college physics students.

A kilobyte rewritable atomic memory


Every day, modern society creates more than a billion gigabytes of new data. To store all this data, it is increasingly important that each single bit occupies as little space as possible. As reported in Nature Nanotechnology today, Floris Kalff and coworkers managed to bring this reduction to the ultimate limit: they built a memory of 1 kilobyte (8,000 bits), where each bit is represented by the position of one single chlorine atom.

With an areal storage density exceeding 500 Terabits per square inch, the memory outperforms existing state-of-the-art harddisk drives by three orders of magnitude. In theory, with this storage density all books ever written by mankind could be spelled out on the surface of a postage stamp.

Apart from being the largest atomically assembled architecture ever created, the memory also features the first demonstration of atomic-scale markers that allow the STM tip to navigate through the large array of bits. Markers indicate the start and end of each line, but can also state if a sector cannot be used for data storage due to contamination or a crystal defect. Such protocols are crucial for scaling-up technology beyond a few hundred bits.

The movie below demonstrates the mechanism of the atomic storage memory.


Check here for an overview of press coverage of ‘the kilobyte’.