Presentation Information
[16a-W9_327-1]In-Plane Thermal Conductivity of Suspended Twisted Bilayer Graphene Nanoribbons
〇TASHI XU1, BIN XU1, RULEI GUO1, TAKASHI KODAMA2, JUNICHIRO SHIOMI1 (1.Univ. Tokyo, 2.Kyushu Tech.)
Keywords:
2D Materials,Graphene,Thermal Conductivity
Two-dimensional materials and moiré superlattice systems exhibit remarkable electrical transport properties. Among them, twisted bilayer graphene (TBG) is particularly notable for its strongly correlated electronic states and superconductivity at certain “magic’’ twist angles, making it a major research focus in condensed matter physics and two-dimensional materials science. However, despite the excellent electrical performance of devices based on these materials, thermal management and heat dissipation remain critical challenges, highlighting the importance of understanding their internal thermal transport behavior. Experimental investigations of thermal transport in TBG nevertheless remain limited. In this work, we report a systematic study of the in-plane thermal conductivity of suspended TBG nanoribbons using a T-type steady-state thermal conductivity measurement method. The nanoribbons have a fixed length of 750 nm and widths ranging from 185 to 580 nm, resulting in an in-plane thermal conductivity spanning 153.3 to 409.3 W/m·K at 280 K. We find that wider nanoribbons exhibit higher in-plane thermal conductivity, revealing a pronounced size effect in TBG nanoribbons. Raman analysis indicates that the internal defect density remains essentially unchanged across different widths, ruling out defect scattering as the dominant mechanism and suggesting that the observed size dependence primarily originates from phonon boundary scattering imposed by geometric confinement. In addition, variations in thermal conductivity among samples with the same width are attributed to differences in twist angle, which provides an additional modulation channel for the in-plane thermal conductivity of TBG. As the nanoribbon width increases, phonons with longer mean free paths increasingly contribute to heat conduction and become more susceptible to Moiré-induced modulation, leading to a larger distribution in the measured in-plane thermal conductivity.