Calendar

Add to Calendar 4/5/2019 1:00 pm 4/5/2019 America/Chicago Condensed Matter Seminar: "Energy, momentum, and spin resolved tunneling of quantum Hall systems" DESCRIPTION:

Transport measurements have revealed remarkable behaviors of the 2D electron system in a magnetic field, such as the quantum Hall effects and the existence of “edge-states” with quantized conductance. However, these and many other measurements have a main limitation in what they tell us about the system: they only have sensitivity to the behavior of electrons near the Fermi energy. Quantum mechanical tunneling, in contrast, can probe electronic states away from the Fermi level. This talk will introduce a contactless tunneling method that utilizes millions of short electrical pulses to induce tunneling currents into and out of 2D electronic systems and yields precise tunneling spectra of 2D system even in regimes where it is electrically insulating. The measurements have revealed remarkable new physics such as: (1) a sharp resonance in tunneling that arises from vibrations of 2D electrons in a “Wigner Crystal”; (2) structure appearing in tunneling spectra that give a direct measurement of the short-range interactions between electrons; (3) measurement and visualization of the 2D energy levels as a function of momentum; (4) observation of polarons and a novel phonon analog of the vacuum Rabi splitting; and (5) measurement of the unusual spin-polarization of the 2D electronic system in magnetic field.

\n\nSPEAKER: Ray Ashoori, Massachusetts Institute of Technology
190 ESB false

Condensed Matter Seminar: "Energy, momentum, and spin resolved tunneling of quantum Hall systems"

Speaker Ray Ashoori, Massachusetts Institute of Technology
Date: 4/5/2019
Time: 1 p.m.
Location: 190 ESB
Sponsor: Physics - Condensed Matter
Event Type: Seminar/Symposium
 

Transport measurements have revealed remarkable behaviors of the 2D electron system in a magnetic field, such as the quantum Hall effects and the existence of “edge-states” with quantized conductance. However, these and many other measurements have a main limitation in what they tell us about the system: they only have sensitivity to the behavior of electrons near the Fermi energy. Quantum mechanical tunneling, in contrast, can probe electronic states away from the Fermi level. This talk will introduce a contactless tunneling method that utilizes millions of short electrical pulses to induce tunneling currents into and out of 2D electronic systems and yields precise tunneling spectra of 2D system even in regimes where it is electrically insulating. The measurements have revealed remarkable new physics such as: (1) a sharp resonance in tunneling that arises from vibrations of 2D electrons in a “Wigner Crystal”; (2) structure appearing in tunneling spectra that give a direct measurement of the short-range interactions between electrons; (3) measurement and visualization of the 2D energy levels as a function of momentum; (4) observation of polarons and a novel phonon analog of the vacuum Rabi splitting; and (5) measurement of the unusual spin-polarization of the 2D electronic system in magnetic field.

To request disability-related accommodations for this event, please contact the person listed above, or the unit hosting the event.

Event Mailing List

Receive Illinois Physics events weekly in your inbox.

Sign-up!


Remove me!