Saiz Bretín, MartaMedrano Sandonas, L.Gutierrez, R.Cuniberti, G.Domínguez-Adame Acosta, Francisco2023-06-172023-06-172019-04-262469-995010.1103/PhysRevB.99.165428https://hdl.handle.net/20.500.14352/13341©2019 American Physical Society Work at Madrid was supported by the Agencia Estatal de Investigacion of Spain (Grants No. MAT2016-75955 and No. MAT2016-63955). This work has also been partly supported by the German Research Foundation (DFG) within the Cluster of Excellence "Center for Advancing Electronics Dresden." We acknowledge the Center for Information Services and High Performance Computing (ZIH) at TU Dresden for providing computational resources.Recent progress in nanostructuring of materials opens up possibilities to achieve more efficient thermoelectric devices. Nanofilms, nanowires, and nanorings may show increased phonon scattering while keeping good electron transport, two of the basic ingredients for designing more efficient thermoelectric systems. Here we argue that graphene nanorings attached to two leads meet these two requirements. Using a density-functional parametrized tight-binding method combined with Green's function technique, we show that the lattice thermal conductance is largely reduced as compared to that of graphene nanoribbons. At the same time, numerical calculations based on the quantum transmission boundary method, combined with an effective transfer matrix method, predict that the electric properties are not considerably deteriorated, leading to an overall remarkable thermoelectric efficiency. We conclude that graphene nanorings can be regarded as promising candidates for nanoscale thermoelectric devices.engjournal articlehttp://dx.doi.org/10.1103/PhysRevB.99.165428https://journals.aps.org/open access538.9Lattice thermal-conductivityThermoelectric figureMeritEnhancementPerformanceFanoFísica de materialesFísica del estado sólido2211 Física del Estado Sólido