Evidence for bulk superconductivity in pure bismuth single crystals at ambient pressure
Evidence for bulk superconductivity in pure bismuth single crystals at ambient pressure
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DOI：
10.1126/science.aaf8227
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发表时间：
2017-01-06
期刊：
影响因子：
56.9
通讯作者：
Ramakrishnan, S.
中科院分区：
文献类型：
--
作者：
Prakash, Om;Kumar, Anil;Ramakrishnan, S.
在环境压力下，大块菱形体铋是一种半金属，在至少10毫开尔文的温度下仍保持正常状态。由于载流子密度极低，大块铋的超导性被认为是不可能的。我们在环境压力下观察到纯铋单晶在0.53毫开尔文以下的大块超导性，在0开尔文下估计临界磁场为5.2微特斯拉。铋的超导性不能用传统的Bardeen-Cooper-Schrieffer理论来解释，因为它的绝热近似对铋不成立。未来的理论工作将需要理解低载流子密度和不寻常带结构的系统（如铋）在非绝热极限下的超导性。
At ambient pressure, bulk rhombohedral bismuth is a semimetal that remains in the normal state down to at least 10 millikelvin. Superconductivity in bulk bismuth is thought to be unlikely because of the extremely low carrier density. We observed bulk superconductivity in pure bismuth single crystals below 0.53 millikelvin at ambient pressure, with an estimated critical magnetic field of 5.2 microteslas at 0 kelvin. Superconductivity in bismuth cannot be explained by the conventional Bardeen-Cooper-Schrieffer theory because its adiabatic approximation does not hold true for bismuth. Future theoretical work will be needed to understand superconductivity in the nonadiabatic limit in systems with low carrier densities and unusual band structures, such as bismuth.