De meningen ge-uit door medewerkers en studenten van de TU Delft en de commentaren die zijn gegeven reflecteren niet perse de mening(en) van de TU Delft. De TU Delft is dan ook niet verantwoordelijk voor de inhoud van hetgeen op de TU Delft weblogs zichtbaar is. Wel vindt de TU Delft het belangrijk - en ook waarde toevoegend - dat medewerkers en studenten op deze, door de TU Delft gefaciliteerde, omgeving hun mening kunnen geven.

Posts tagged visitors

Mikhail Titov

has been visiting on Wednesday to give the Quantum Nanoscience seminar among other things. I know him from 2000 when he was a post doc with Carlo Beenakker. Now he is a faculty in Nijmegen.

His work now is mostly in bulk transport, graphene being the most popular and useful application. The talk was about linear magnetoresistance and sign-reversed Coulomb drag in compensated Hall regime. This may sound involved, however, it was quite a fun to follow and understand that all miracles of experiment can be solved if you think clearly, simply but beyond a beaten track.

I even had an urge to do some Coulomb drag: I used to like the phenomenon, yet last time I look at it was 1999.

Charles Markus

from Copenhagen, a brilliant experimentalist who has now mostly concentrated on Majoranization of semiconducting nanowires by connecting those to superconductors – has given a talk on Thursday.

He started with reporting successes in nanowire growth: nanowires can be better contacted with superconductors, and can be made in t and h shapes. He has shown “hard gap” – looked good, finally in place after years of technological search.

Then we got the report on experimental results – some fresh, right from the oven. The results in “Delft geometry” seemed clean but I did not quite see the gap as hard as promised. The results in “Copenhagen geometry” were a superconducting island has been attached to the nanowire seemed more fun – I will have to revise those carefully.

Wilfred van der Wiel

from Twente University gave a Nanoscience seminar on Wednesday. I vividly remember him as an outstanding PhD student, have not seen him for years and was delighted to see no significant change: in the position of full professor, he reminds sharp, handsome, nice and does outstanding research.

There were two topics. First one: Wilfred has investigated the conductance (well, if you can call inverse GigaOhm a conductance) of molecular wires thread in zeolyte crystal. The conductance could be changed by order of magnitude by tiny magnetic field in millitesla range. The mechanism of the effect must be related to nuclear spins and as such is the same as for the spin-blockade lifting in double quantum dots. The details remain unclear for me: yet the effect is there and is a record-strong.

The second topic has fascinated me even more. The physics was rather simple: Coulomb blockade in a pile of gold nanoparticles carelessly collected between a multitude of electrodes. A neat physical realization of complete and hopelessly incomprehensible mess. Yet it appears that that it is the mess that motivated the researcher. Wilfred managed to demonstrate that with the proper tuning (based on genetic algorithm) the pile can work as any of the logical gates! I reckon this work will have a big philosophical impact (seriously). It proves that electronic components can be made from anything (substitute “anything” with a stronger word if you like).

Christian Glattli

from Saclay has visited us on Wednesday this week. We have had an opportunity to chat about his research on graphene plasmonics and his plans to utilize edge channels in graphene, as well as about my plans with chiral electrons.

His talk was about “levitons”, his recent research on noise in quantum point contact. This drew me very philosophical: I began to think about most general definition of a particle and even ask Christian about)).

© 2011 TU Delft