Colloquium Talk
Professor Joe Kraisler, Amherst College
Thursday October 26, 2023 at 3PM
Rocky 300

Title: Topological Insulators and the SSH Model

Abstract: Electronic band theory was one of the early 20th century achievements of quantum mechanics and placed solids into three categories: conductors, semiconductors, and insulators. However, starting in the 1980s with the discovery of the Quantum Hall Effect, a new phase of matter known as Topological Insulators (TIs) were theorized and eventually realized. These materials act as insulators in the interior, or bulk, while allowing electrons to freely move along the boundary, or edge, of the material. Additionally, there is a relationship between the a) number of states which exist on the boundary and b) a property of the interior which is protected under small defects. This relationship is often referred to as the Bulk-Edge Correspondence.

We will study the simplest example of a 1-dimensional topological insulator, the SSH (Su-Schrieffer-Heeger) model of polyacetylene, and prove the bulk edge correspondence for this particular system. No previous physics knowledge is required.