Pressure-induced evolution of band structure in black phosphorus studied by P31 NMR
Pressure-induced evolution of band structure in black phosphorus studied by P31 NMR
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DOI：
10.1103/physrevb.101.161408
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发表时间：
2019-05
影响因子：
3.7
通讯作者：
T. Fujii;Y. Nakai;Y. Akahama;K. Ueda;T. Mito
中科院分区：
文献类型：
--
作者：
T. Fujii;Y. Nakai;Y. Akahama;K. Ueda;T. Mito
用能带结构计算预测了二维层状半导体黑磷(BP)是一种很有前途的压致Dirac体系，并用P-核磁共振方法对其进行了研究。还进行了能带计算以估算态密度D(E)$。用所得的方法很好地再现了半导体相核自旋晶格驰豫速率$1/T_1随温度和压力的变化关系，所得到的半导体能隙随压力的变化规律与前人的报道相一致，从而证实了BP带的计算是相当可靠的。用互补的理论计算对$1/T_1$数据进行的分析使我们能够提取必要的信息，如$D(E)$的压力依赖关系和化学势，以及将观测到的$1/T_1$分解为本征贡献和外在贡献。在1.63 GPa时，$1/T_1的突然增加表明半导体禁带的闭合，导致导电性的提高。
Two-dimensional layered semiconductor black phosphorus (BP), a promising pressure induced Dirac system as predicted by band structure calculations, has been studied by $^{31}$P-nuclear magnetic resonance. Band calculations have been also carried out to estimate the density of states $D(E)$. The temperature and pressure dependences of nuclear spin lattice relaxation rate $1/T_1$ in the semiconducting phase are well reproduced using the derived $D(E)$, and the resultant pressure dependence of semiconducting gap is in good accordance with previous reports, giving a good confirmation that the band calculation on BP is fairly reliable. The present analysis of $1/T_1$ data with the complemental theoretical calculations allows us to extract essential information, such as the pressure dependences of $D(E)$ and chemical potential, as well as to decompose observed $1/T_1$ into intrinsic and extrinsic contributions. An abrupt increase in $1/T_1$ at 1.63GPa indicates that the semiconducting gap closes, resulting in an enhancement of conductivity.