[RpL 1277] IRQ'2020: Lecture by Sergey Kubatkin 'Epitaxial graphene on Silicon Carbide: physics, chemistry and electronic applications'

[Alexander Semenov]

Dear all,
Today, on Tuesday November 17, at 17.00 Moscow time (15.00 CET, 14.00 GMT), lecture 'Epitaxial graphene on Silicon Carbide: physics, chemistry and electronic applications' will be given by Sergey Kubatkin, professor at Chalmers University of Technology. Please find below the abstract.
Link to Zoom meeting: https://zoom.us/j/8976647786?pwd=SjBSTVNqRG1uaCsrYjJDVit5eTduUT09
(For those who plan to get certificate and want to be counted by as accurately: 1) please check that your Zoom nick allows to identify you unambiguously; 2) after entering, send a private message via the chat, with any text,  to the person named 'Registration').
Link to the site of the School with the Program:
https://irq2020.quant.physics.mpgu.edu/
Sincerely,
On behalf of Organisers of IRQ'2020,
Alexander Semenov
P. S. If you don't want to receive our emails, please respond to this one by an email containing word 'NO' in the body.
Sergey Kubatkin
Epitaxial graphene on Silicon Carbide: physics, chemistry and electronic applications
Abstract
Peculiar electronic properties of graphene promise interesting electronic applications, but graphene faces tough competition with mature conventional technologies: semiconductors and superconductors. In my talk I plan to describe how these challenges can be met with a wafer-scale graphene on Silicon Carbide (SiC) – epigraphene.
I plan to start from a general introduction into material properties of epigraphene, describe the issues with its uniform doping towards the Dirac point and our approach to solving these challenges. Unique to epigraphene, anomalously strong pinning of the Fermi level leads to extremely wide quantum Hall plateaux in epigraphene, making it an ideal material for quantum resistance metrology – here epigraphene surpasses performance of 2D electron gas formed in traditional semiconductors. Uniform doping of epigraphene in combination with strong intervalley scattering leads to robust quantum localization of charge carriers in graphene, making this material a good thermometer down to 100 mK; application of relatively weak magnetic field allows further extension of the temperature range to sub 100 mK temperatures.
The wafer-scale nature of epigraphene allows for measurements on large samples and this facilitates studying the response of this material to THz radiation, where the beam cannot be collimated tightly. I plan to present a couple of examples of response of graphene charge carriers to relatively strong THz radiation, obtained in collaboration with the group of Prof. Ganichev from Regensburg, Germany. Moreover, using epigraphene as a fast thermometer, we have demonstrated a heterodyne detection of THz radiation with promising potential for THz astronomy. The optimistic projection of our preliminary data result in an expected mixer noise temperature as low as 36 K, with a gain bandwidth exceeding 20 GHz, and local oscillator power requirements  of < 100 pW . This projection would outperform superconductor-based mixers, which are inherently limited both in speed and in the frequency range, particularly for large heterodyne arrays, which are in a high demand among astronomers.
In collaboration with the group of Prof. Pekola from Aalto University, Finland, we explore an opportunity to use quantum interference of charge carriers in epigraphene for direct detectors of GHz-THz radiation. In our study of electron- phonon coupling in epigraphene to the substrate phonons at mK temperatures, we show that it obeys the T4 dependence characteristic for clean two-dimensional conductor. Based on our measurements, we predict the noise-equivalent power of ~ 10^{−22} W/√Hz for epigraphene direct detection bolometer at the low end of achievable temperatures.