Department of Materials Science and Engineering, Centennial Campus, North Carolina State University , Raleigh, North Carolina 27695-7907, United States.
Materials Science Division, Army Research Office , Research Triangle Park, North Carolina 27709, United States.
ACS Nano. 2017 Jun 27;11(6):5351-5357. doi: 10.1021/acsnano.7b01294. Epub 2017 May 5.
We report high-temperature superconductivity in B-doped amorphous quenched carbon (Q-carbon). This phase is formed after nanosecond laser melting of B-doped amorphous carbon films in a super-undercooled state and followed by rapid quenching. Magnetic susceptibility measurements show the characteristics of type-II Bardeen-Cooper-Schrieffer superconductivity with a superconducting transition temperature (T) of 36.0 ± 0.5 K for 17.0 ± 1.0 atom % boron concentration. This value is significantly higher than the best experimentally reported T of 11 K for crystalline B-doped diamond. We argue that the quenching from metallic carbon liquid leads to a stronger electron-phonon coupling due to close packing of carbon atoms with higher density of states at the Fermi level. With these results, we propose that the non-equilibrium undercooling-assisted synthesis method can be used to fabricate highly doped materials that provide greatly enhanced superconducting properties.
我们报告了掺硼非晶淬火碳（Q 碳）中的高温超导性。这种相是在超过冷状态下纳秒激光熔化掺硼非晶碳薄膜并随后快速淬火后形成的。磁化率测量显示出 II 型 Bardeen-Cooper-Schrieffer 超导性的特征，对于 17.0 ± 1.0 原子%的硼浓度，超导转变温度（T）为 36.0 ± 0.5 K。这个值明显高于对于结晶掺硼金刚石实验报告的最佳 T 值 11 K。我们认为，由于碳原子的紧密堆积和费米能级处更高的态密度，从金属碳液体淬火会导致更强的电子-声子耦合。基于这些结果，我们提出非平衡过冷辅助合成方法可用于制造高掺杂材料，从而大大提高超导性能。
