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摘要: 报道在低温(4.2K)条件下利用STM/STS实验方法对过渡族金属二硫族化合物1T-TaSe2的观测结果,明确得到了1T-TaSe2中电荷密度波超晶格以及原子晶格的直观图像,并且给出了有关电荷密度波能隙的隧道谱结果,通过选择高纯度Fc以及不锈钢金属材料作为探针,还得到了单个隧道结构中单电子隧道(SET)效应的实验证据,即“库仑阻塞”(Coulomb blocade)效应,并以此说明STM隧道结中探针表面氧化层对实验结果的影响。
Abstract: We have used scanning tunneling microscopy working at 4.2 K to study the transition metal dichalcogenide 1T-TaSe2. The charge density wave (CDW) superstructure (131/2α0×131/2α0) and atomic modulation are well resolved, as well as the associated CDW energy gap. In particular we used high purity iron as tip material and demonstrated clearly the existence of single electron tunnel-ing (so-called Coulomb blocade) effects, further experiments with stainless steel tips also confirmed this observation. It is pointed out that during STM/STS studies tips covered with oxides are very likely to display Coulomb blocade effects due to their small capacitance. Therefore, extra cautious are needed when analyzing spectroscopic features in the area that could be affected by Coulomb blocade effects. At the mean time, high quality scanning images can still be regularly obtained through reso-nant tunneling process.