Northwestern Events Calendar

Feb
11
2021

CMP Seminar: Pallab Goswami: Higher-order topology of quantum and classical materials

When: Thursday, February 11, 2021
4:00 PM - 5:00 PM Central

Where: Online

Audience: Faculty/Staff - Student - Post Docs/Docs - Graduate Students

Contact: Yas Shemirani  

Group: Physics and Astronomy Condensed Matter Physics Seminars

Category: Academic

Description:

Both quantum and classical many-particle systems can support topological states of matter, which are immune to smooth, local perturbations. The diagnosis of bulk topology of real materials often relies upon identifying spectroscopic evidence of topologically protected, gapless, surface-states. This heuristic approach entirely misses out many phases, collectively known as the higher-order topological insulators, which only exhibit gapped, surface-states. Such phases are being actively studied in diverse systems, like solid-state materials, quantum circuits, photonic crystals, and mechanical meta-materials.  

However, the organizing principles and the computational diagnosis of higher-order topological insulators in real materials are obscured by the lack of stable, bulk topological invariants. In this talk, I will outline a recently developed, theoretical framework for addressing the bulk topology and the bulk-boundary correspondence of higher-order topological insulators. I will describe the first, comprehensive topological classification of ab initio band structures of Dirac semimetal Na3Bi, and compensated semimetals, like bismuth and antimony. I will also discuss new predictions for the quadrupolar and the octupolar topological insulators, realized in various engineered systems.   

Pallab Goswami, Northwestern University

Host: Jens Koch

Zoom info:
Please email yassaman.shemirani@northwestern.edu if you would like access to the Zoom meeting link.

Keywords: Physics, Astronomy, Condensed Matter

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