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May 26 – 31, 2024
Western University
America/Toronto timezone
Welcome to the 2024 CAP Congress Program website! / Bienvenue au siteweb du programme du Congrès de l'ACP 2024!

(G) (POS-64) Distortions of Transition Metal Dichalcogenides: Quantum Loops on the Triangular Lattice

May 28, 2024, 5:57 PM
2m
PAB Hallways (Western University)

PAB Hallways

Western University

Poster not-in-competition (Graduate Student) / Affiche non-compétitive (Étudiant(e) du 2e ou 3e cycle) Condensed Matter and Materials Physics / Physique de la matière condensée et matériaux (DCMMP-DPMCM) DCMMP Poster Session & Student Poster Competition (11) | Session d'affiches DPMCM et concours d'affiches étudiantes (11)

Speaker

Mr Ashland Knowles (Brock University)

Description

Transition Metal Dichalcogenides (TMDs) are layered semiconducting materials of the form MX$_2$, where M represents a transition metal atom and X represents a chalcogen. In the 1T structural phase, the chalcogens provide an octahedral environment for each metal atom. We propose a quantum loop model to explain the nature of bonding in these materials. We focus on metal atoms from group VI of the periodic table (e.g., MoS$_2$, MoSe$_2$, WS$_2$, WSe$_2$) which have two valence electrons in their $d$ orbitals. These electrons reside in t$_{2g}$ orbitals that point towards the six nearest neighbors on the underlying triangular lattice. We argue that these form covalent bonds that connect together to form loops. Loops can be formed in a large number of ways, leading to a resonating valence bond picture. We numerically enumerate all allowed loop configurations for small sizes of systems. We then construct a minimal effective Hamiltonian with local ‘potential energy’ and ‘kinetic energy’ terms. The kinetic energy term reflects processes where neighboring loops are cut and merged to form new loops, or a single loop changes shape. The potential energy term is due to the repulsion of proximate bonds. We construct a phase diagram, finding two prominent stripe-like phases. One of these closely resembles the 1T' structure, which is a well-known stripe-like distortion of the 1T phase. We discuss further tests of these ideas, e.g., in impurity-induced textures.

Keyword-1 TMDs
Keyword-2 Quantum loop model

Primary author

Mr Ashland Knowles (Brock University)

Co-authors

Dr Ganapathy Baskaran (Indian Institute of Technology, Madras; Perimeter Institute for Theoretical Physics, Waterloo) Dr Ganesh Ramachandran (Brock University)

Presentation materials

There are no materials yet.