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Cu3Sn, a well-known intermetallic compound with a high melting temperature and thermal stability, has found numerous applications in microelectronics, 3D printing, and catalysis. However, the relationship between the material's thermal conductivity anisotropy and its complex anti-phase boundary superstructure is not well understood. Here, frequency domain thermoreflectance was used to map the thermal conductivity variation across the surface of arc-melted polycrystalline Cu3Sn. Complementary electron backscatter diffraction and transmission electron microscopy revealed the thermal conductivity in the principal a, b, and c orientations to be 57.6, 58.9, and 67.2 W/m-K, respectively. Density functional theory calculations for several Cu3Sn superstructures helped examine thermodynamic stability factors and evaluate the direction-resolved electron transport properties in the relaxation time approximation. The analysis of computed temperature- and composition-dependent free energies suggests metastability of the known long-period Cu3Sn superstructures while the transport calculations indicate a small directional variation in the thermal conductivity. The ∼15% anisotropy measured and computed in this study is well below previously reported experimental values for samples grown by liquid-phase electroepitaxy. 

The interaction of graphene with water molecules under an applied electric field is not thoroughly understood, yet this interaction is important to many thermal, fluidic, and electrical applications of graphene. In this work, the effect of electrical doping of graphene on water adsorption is studied through adsorption isotherms and current–voltage (IV) characterizations as a function of the Fermi level. The water adsorption onto graphene increases by ≈15% and the doping levels increase by a factor of three with a gate‐to‐graphene voltage of +20 or −20 V compared to 0 V for sub‐monolayer adsorption. This change in uptake is attributed to the increase in density of state of graphene upon electrical‐doping, which changes the Coulombic and van der Waals interactions. The water adsorption onto graphene is either n‐ or p‐doping depending on the applied gate‐to‐graphene voltage. The ambi‐doping nature of water onto graphene is due to the polar nature of water molecules, so the doping depends on the orientation of the water molecules.