High-quality single crystals of ${\left(\mathrm{PbSe}\right)}_5{\left({\mathrm{Bi}}_2{\mathrm{Se}}_3\right)}_{3m}$ were grown and analyzed by nuclear magnetic resonance (NMR) spectroscopy. We report on ${}^{77}\mathrm{Se}$ and ${}^{207}\mathrm{Pb}$ NMR shifts and nuclear spin-lattice relaxation measurements in the naturally formed heterostructure homology ${\left(\mathrm{PbSe}\right)}_5{\left({\mathrm{Bi}}_2{\mathrm{Se}}_3\right)}_{3m}$ with $m=1 \left({\mathrm{Pb}}_5{\mathrm{Bi}}_6{\mathrm{Se}}_{14}\right)$ and $m=2 \left({\mathrm{Pb}}_5{\mathrm{Bi}}_{12}{\mathrm{Se}}_{23}\right)$. A distinct site-specific contribution has been detected for both nuclei as a function of temperature, which reveals an electronic changeover from a semiconducting ${\mathrm{Pb}}_5{\mathrm{Bi}}_6{\mathrm{Se}}_{14}$ to a semimetalliclike ${\mathrm{Pb}}_5{\mathrm{Bi}}_{12}{\mathrm{Se}}_{23}$ system with nontrivial band structure features near the Fermi level. The temperature dependences of the relaxation rates are dominated by significant changes in the topology of energy dispersions accompanied with band edges and crossings in the region of the Fermi surface. These results, which interrogate nuclear spin interactions from selected atomic sites, clearly expose the effects of the added ${\mathrm{Bi}}_2{\mathrm{Se}}_3$ layer on the crystal and electronic structure of ${\mathrm{Pb}}_5{\mathrm{Bi}}_{12}{\mathrm{Se}}_{23}$. These findings provide direct microscopic insight into the unconventional and dual nature of the electronic structure of these homologous thermoelectric and topologically nontrivial compounds.

中文翻译：

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同源成员Pb5Bi6Se14和Pb5Bi12Se23的能带结构中非平凡费米表面特征的演变

高品质的单晶 ${（\mathrm{铅硒}）}_5{（{\mathrm{双}}_2{\mathrm{硒}}_3）}_{3米}$生长并通过核磁共振（NMR）光谱进行分析。我们报告${}^{77}硒$ 和 ${}^{207}\mathrm{铅含量}$ 天然形成的异质结构同源性中的NMR位移和核自旋晶格弛豫测量 ${（\mathrm{铅硒}）}_5{（{\mathrm{双}}_2{\mathrm{硒}}_3）}_{3米}$ 与 $米=\mathrm{1个} （{\mathrm{铅含量}}_5{\mathrm{双}}_6{\mathrm{硒}}_{14}）$ 和 $米=2 （{\mathrm{铅含量}}_5{\mathrm{双}}_{12}{\mathrm{硒}}_{23}）$。已检测到两个原子核都随温度而异的特定于位点的贡献，这揭示了半导体的电子转换${\mathrm{铅含量}}_5{\mathrm{双}}_6{\mathrm{硒}}_{14}$ 到半金属般 ${\mathrm{铅含量}}_5{\mathrm{双}}_{12}{\mathrm{硒}}_{23}$费米能级附近具有非平凡带结构的系统。弛豫速率的温度依赖性主要由能量分散的拓扑结构的显着变化决定，这些变化伴随着费米表面区域中的能带边缘和交叉。这些结果询问了选定原子位点的核自旋相互作用，清楚地揭示了添加的影响。${\mathrm{双}}_2{\mathrm{硒}}_3$ 晶体和电子结构层 ${\mathrm{铅含量}}_5{\mathrm{双}}_{12}{\mathrm{硒}}_{23}$。这些发现为这些同源热电和拓扑学上不重要的化合物的电子结构的非常规和双重性质提供了直接的微观见解。