Direct thermal resistance measurment of a single ripplocation in graphite

Lattice defects in crystalline materials play a critical role in tuning thermal transport, with their properties being highly sensitive to atomic structure. However, characterizing such structure-property relationships is hampered by the challenges in directly measuring thermal properties at the single-defect level. Here, we use in-situ electron energy loss spectroscopy in scanning transmission electron microscopy (STEM–EELS) to characterize ripplocation boundaries (RBs)—unique kink-like topological defects inlayered crystalline solids (LCS) —revealing their atomic-scale lattice dynamic features and quantifying local thermal resistance. We find that the interlayer alternating strain field within ~ 5 nm of RBs broadens the phonon bands of out-of-plane and transverse acoustic modes, leading to enhanced phonon scattering and thereby a ~ three- to five-fold increase in local thermal resistance relative to defect-free regions. The obtained typical thermal resistance of ripplocations ranges from 4.69×10 ^− 11 to 8.06×10 ^− 11 m ² K W ^− 1 , exhibiting monotonic dependence on bending angles. These findings establish a quantitative link among ripplocation atomic configurations, phonon features and thermal resistance, providing critical guidelines for defect thermal engineering in LCS. The in-situ characterization paradigm also paves the way for probing single defect thermal properties at the atomic scale.