Thermal rectification through the topological states of asymmetrical length armchair graphene nanoribbons heterostructures with vacancies

TL;DR

This paper theoretically investigates electron heat current in asymmetrical armchair graphene nanoribbon heterostructures with vacancies, revealing how topological states and structural modifications can enhance heat rectification and reduce phonon heat current.

Contribution

It introduces a novel approach to control heat rectification in graphene nanoribbons by manipulating topological states, asymmetrical lengths, and vacancy positioning to optimize thermal management.

Findings

Significant heat rectification achieved via inter-TS Coulomb interactions.

Vacancies effectively suppress phonon heat current without affecting topological states.

Asymmetrical lengths enhance heat rectification ratio ($_Q$).

Abstract

We present a theoretical investigation of electron heat current in asymmetrical length armchair graphene nanoribbon (AGNR) heterostructures with vacancies, focusing on the topological states (TSs). In particular, we examine the 9-7-9 AGNR heterostructures where the TSs are well-isolated from the conduction and valence subbands. This isolation effectively mitigates thermal noise of subbands arising from temperature fluctuations during charge transport. Moreover, when the TSs exhibit an orbital off-set, intriguing electron heat rectification phenomena are observed, primarily attributed to inter-TS electron Coulomb interactions. To enhance the heat rectification ratio ($\eta_Q$), we manipulate the coupling strengths between the heat sources and the TSs by introducing asymmetrical lengths in the 9-AGNRs. This approach offers control over the rectification properties, enabling significant enhancements. Additionally, we introduce vacancies strategically positioned between the heat sources and the TSs to suppress phonon heat current. This arrangement effectively reduces the overall phonon heat current, while leaving the TSs unaffected. Our findings provide valuable insights into the behavior of electron heat current in AGNR heterostructures, highlighting the role of topological states, inter-TS electron Coulomb interactions, and the impact of structural modifications such as asymmetrical lengths and vacancy positioning. These results pave the way for the design and optimization of graphene-based devices with improved thermal management and efficient control of electron heat transport.