Science http://doi.org/csbb (2018)

For decades, thermal management has been a serious engineering hurdle in the design of electronic devices and circuits. A rapid reduction in transistor size has expanded the excess heat issue into the nanoscale, calling for the development of new materials for efficient heat dissipation. Now, building on recent theoretical predictions, Sang Kang and co-workers experimentally obtain a defect-free single-crystal boron arsenide (BAs) exhibiting a thermal conductivity on par with the best known heat conductors.

The performed structural analysis reveals the single-crystalline nature and zinc-blende face-centred cubic crystal structure of the synthesized BAs. The researches then use ultrafast optical pump–probe spectroscopy to study the heat transport properties of BAs, and compare their findings with similar measurements performed on diamond and cubic boron nitride samples. The measurements confirm ballistic transport in all studied samples including the BAs crystals, which show a thermal conductivity of 1,300 W mK–1 at room temperature, the second highest value among all known bulk materials. According to the report, the efficient heat conduction of the crystals stems from the enhanced phonon mean free path enabled by the unique BAs phonon band structure.