Exploration of crystallographic defects in topological insulator metamaterials

Yamada, Sasha Seneca

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https://hdl.handle.net/2142/114109 Copy

Description

Title

Exploration of crystallographic defects in topological insulator metamaterials

Author(s)

Yamada, Sasha Seneca

Issue Date

2021-12-08

Director of Research (if dissertation) or Advisor (if thesis)

Bahl, Gaurav

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• topological insulators
• crystallographic defects

Abstract

Topological phases of matter have attracted the interest of physicists and engineers due to their novel transport properties and ability to protect robust states at material boundaries. These phases of matter occur when symmetries quantize and protect an invariant material property. While initially thought to be unusual behavior, computational analysis of stoichiometric materials has revealed that over 27% of all materials in nature are topologically non-trivial. The prevalence of these materials provides further cause to study their behavior; however, it remains an experimental challenge to exercise precise control of materials at an atomic level. Fortunately, the topological properties of these materials are governed by the wave-nature of electrons which allows classical analogues to be constructed from metamaterials. Such metamaterials have been constructed using mechanical, electronic, and photonic platforms to study topological phenomena. This thesis describes the construction of circuit-based resonator arrays and their application to experimentally investigate how crystallographic defects interact with a material's topology. Specifically, partial dislocation defects in multipole topological insulators are considered. It is observed that these defects can trap robust bound states at their defect core, which provides a pathway to embed protected topological states deep within the bulk of a material.

Graduation Semester

2021-12

Type of Resource

Thesis

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http://hdl.handle.net/2142/114109

Copyright and License Information

Copyright 2021 Sasha Seneca Yamada

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