Claes Thelander

Research:

The research in my group is primarily focused on studying transport in semiconductor nanowires of different narrow bandgap materials such as InAs, InSb, GaSb, InP and their alloys. Here we explore the electronic structure of novel crystal phases, and how these phases can be used in device structures and for transport physics.
One particular focus is quantum dots (artificial atoms) and coupled quantum dots (artificial molecules). We have developed a new method to create tunable coupled quantum dots with extremely strong confinement, which are ideal for exploring electron interactions and spin physics. 
Ongoing work involves exploring Kondo physics of coupled dots, quantum ring formation and orbital enhanced g-factors, coupling to ferromagnetic and superconducting contacts

Click here to see a recorded presentation (22 min) from EMRS Fall meeting 2021 on the topic of "Quantum rings in polytypic nanowires".

Teaching:

Course responsible and lecturer: Processing and Device Technology (Process- och komponentteknologi) FFFF10/FYSD13. The course is given in the beginning of the fall (LP1, 7.5 HP).

Information regarding publications:

To find a complete list of published journal papers that I have authored or co-authored please visit my web of science (Publons/ResearcherID) page or ORCID page:  (Publication metrics from Web of Science, 2022: 111 publ., h-index 39, average 64 citations/publ.)

Image Gallery:

Formation of artificial molecules based on coupled quantum dots within nanowires of InAs. https://doi.org/10.1021/acs.nanolett.7b04090

Adding electron spins one-by-one to an empty coupled quantum dot. Electrical conductance measurements done at T = 15 mK. https://doi.org/10.1103/PhysRevB.98.245305

Ever wondered what happens if you couple two quantum dots in two points? No? Well we figured it out anyway, and it is pretty interesting... (https://doi.org/10.1038/s41467-019-13583-7)

Here we compared quantum rings of different symmetry in a magnetic field, and stumbled upon interesting physics. http://dx.doi.org/10.1021/acs.nanolett.1c03882

Effect of a magnetic field on orbital interaction. When half a magnetic flux quantum threads an artificial ring molecule composed of two "atoms", the condition for ring formation is reversed. For zero flux, the orbital parities need to be different (odd/even), but for a flux of e/2h, they should be the same. 

Who does not like diamonds? These are pretty cool (T = 15 mK). Check this thesis for more cool diamonds.

The images show some steps involved in processing contacts to nanowires for electrical characterization. The center contact is a superconductor where the goal was to split Cooper pair spins into the two quantum dots. Please check this link (also found to the right) for more information about this contact process and how we have optimized it.

A race to the best Esaki tunnel diode, or to the moon? American teams won both races, but we almost got there... here.

Gold particles (20 nm) pushed around in an AFM (left: AFM, right: SEM). I gave this as a "small" gift to my supervisor Lars when he turned 50. Can you find the odd one out ? (One blob was apparently just some… blob)

A tiny electro-mechanical switch from two carbon nanotubes, moved back and forth with the tip of an AFM. https://doi.org/10.1088/0957-4484/13/1/323

Now that we have carbon nanotubes and nanoparticles, why not combine them into a tiny single-electron transistor? This one may have ”worked” during a very cold night in Antarctica. The 7 nm Au particle is responsible for the dominant features in the data, whereas the nanotube contacts produced the smaller ”ripples". https://doi.org/10.1063/1.1405154

Dissection of a carbon nanotube rope using an AFM with in-situ electrical feedback. https://doi.org/10.1088/0957-4484/13/1/323