Calendar

Add to Calendar 12/4/2017 12:00 pm 12/4/2017 America/Chicago Special ICMT Seminar: Modern semiclassical theory of magnetic oscillations and breakdown DESCRIPTION:

The modern semiclassical theory of a Bloch electron in a magnetic field now encompasses the orbital magnetic moment and the geometric phase. These two notions are encoded in the Bohr-Sommerfeld quantization condition as a phase ($\lambda$) that is subleading in powers of the field; $\lambda$ is measurable in the phase offset of the de-Haas-van-Alphen oscillation, as well as of fixed-bias oscillations of the differential conductance in tunneling spectroscopy. In some solids and for certain field orientations, $\lambda/\pi$ are robustly integer-valued owing to the symmetry of the extremal orbit, i.e.,  they are the topological invariants of magnetotransport. Our comprehensive symmetry analysis identifies solids in any (magnetic) space group for which $\lambda$ is a topological invariant, as well as identifies the symmetry-enforced degeneracy of Landau levels. The analysis is simplified by our formulation of ten (and only ten) symmetry classes for closed, Fermi-surface orbits. Case studies are discussed for graphene, transition metal dichalchogenides, 3D Weyl and Dirac metals, and crystalline and $\Z_2$ topological insulators. Finally, I will discuss extensions of the quantization condition to incorporate quantum tunneling between orbits, known as magnetic breakdown.

\n\nSPEAKER:

Aris Alexandradinata, Yale

190 ESB

false

Special ICMT Seminar: Modern semiclassical theory of magnetic oscillations and breakdown

Speaker Aris Alexandradinata, Yale
Date: 12/4/2017
Time: 12 p.m.
Location:

190 ESB

Sponsor:

Institute for Condensed Matter Physics

Event Type: Seminar/Symposium
 

The modern semiclassical theory of a Bloch electron in a magnetic field now encompasses the orbital magnetic moment and the geometric phase. These two notions are encoded in the Bohr-Sommerfeld quantization condition as a phase ($\lambda$) that is subleading in powers of the field; $\lambda$ is measurable in the phase offset of the de-Haas-van-Alphen oscillation, as well as of fixed-bias oscillations of the differential conductance in tunneling spectroscopy. In some solids and for certain field orientations, $\lambda/\pi$ are robustly integer-valued owing to the symmetry of the extremal orbit, i.e.,  they are the topological invariants of magnetotransport. Our comprehensive symmetry analysis identifies solids in any (magnetic) space group for which $\lambda$ is a topological invariant, as well as identifies the symmetry-enforced degeneracy of Landau levels. The analysis is simplified by our formulation of ten (and only ten) symmetry classes for closed, Fermi-surface orbits. Case studies are discussed for graphene, transition metal dichalchogenides, 3D Weyl and Dirac metals, and crystalline and $\Z_2$ topological insulators. Finally, I will discuss extensions of the quantization condition to incorporate quantum tunneling between orbits, known as magnetic breakdown.

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!