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| Main Authors: | , , |
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| Format: | Preprint |
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2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2409.03819 |
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| _version_ | 1866912358257917952 |
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| author | Knowles, Ashland Baskaran, G. Ganesh, R. |
| author_facet | Knowles, Ashland Baskaran, G. Ganesh, R. |
| contents | Loop arrangements and their quantum superpositions describe several interesting many-particle states. We propose that they also describe bonding in a class of transition metal dichalcogenides. We present an effective quantum loop model for monolayers with 1T structure and a d$^2$ valence electron configuration: materials of the form MX$_2$ (M = Mo, W and X=S, Se, Te) and AM$'$Y$_2$ (A = Li, Na; M$'$ = V, Nb and Y = O, S, Se). Their t$_{2g}$ orbitals exhibit strongly directional overlaps between neighbouring atoms, favouring the formation of valence bonds. A transition metal atom forms two valence bonds, each with one of its neighbours. When connected, these bonds form loops that cover the triangular lattice. We construct a minimal Rokhsar-Kivelson-like model with resonance processes that cut and reconnect loops that run in proximity. The resulting dynamics is more constrained than in traditional quantum dimer models, with a `bending' constraint that arises from orbital structure. In the resulting phase diagram, we find phases that resemble distorted phases seen in materials, viz., the 1T$'$ and trimerized phases. As a testable prediction, we propose that a single d$^1$ or d$^3$ impurity will terminate a loop and give rise to a long-ranged texture. For example, a Ti/Cr defect in LiVO$_2$ will produce one or more domain walls that propagate outward from the impurity. We discuss the possibility of a loop liquid phase that can emerge in these materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2409_03819 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Quantum loops in the 1T transition metal dichalcogenides Knowles, Ashland Baskaran, G. Ganesh, R. Strongly Correlated Electrons Loop arrangements and their quantum superpositions describe several interesting many-particle states. We propose that they also describe bonding in a class of transition metal dichalcogenides. We present an effective quantum loop model for monolayers with 1T structure and a d$^2$ valence electron configuration: materials of the form MX$_2$ (M = Mo, W and X=S, Se, Te) and AM$'$Y$_2$ (A = Li, Na; M$'$ = V, Nb and Y = O, S, Se). Their t$_{2g}$ orbitals exhibit strongly directional overlaps between neighbouring atoms, favouring the formation of valence bonds. A transition metal atom forms two valence bonds, each with one of its neighbours. When connected, these bonds form loops that cover the triangular lattice. We construct a minimal Rokhsar-Kivelson-like model with resonance processes that cut and reconnect loops that run in proximity. The resulting dynamics is more constrained than in traditional quantum dimer models, with a `bending' constraint that arises from orbital structure. In the resulting phase diagram, we find phases that resemble distorted phases seen in materials, viz., the 1T$'$ and trimerized phases. As a testable prediction, we propose that a single d$^1$ or d$^3$ impurity will terminate a loop and give rise to a long-ranged texture. For example, a Ti/Cr defect in LiVO$_2$ will produce one or more domain walls that propagate outward from the impurity. We discuss the possibility of a loop liquid phase that can emerge in these materials. |
| title | Quantum loops in the 1T transition metal dichalcogenides |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2409.03819 |