Tunneling spectroscopy of ultrathin insulating Cu2N films, and single Co adatoms
Tunneling spectroscopy of ultrathin insulating Cu2N films, and single Co adatoms
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超薄绝缘 Cu2N 薄膜和单 Co 吸附原子的隧道光谱
DOI：
10.1116/1.3010720
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发表时间：
2009
影响因子：
1.4
通讯作者：
J. Gupta
中科院分区：
文献类型：
--
作者：
T. Choi;C. D. Ruggiero;J. Gupta
使用扫描隧道显微镜表征 c(2×2)N∕Cu(100)（即 Cu2N）的 1 ML 薄膜的电子结构。通过改变氮覆盖率，制备了多种形态，包括（1）孤立的〜25nm2岛，（2）密堆积岛阵列，和（3）准连续单层膜。作者发现，在所有三种状态下，Cu2N 都充当绝缘体，其带隙超过 4eV。绝缘 Cu2N 薄膜用于控制吸附的 Co 原子与 Cu(100) 表面电子密度的耦合。 Co 在 Cu2N 上的隧道光谱揭示了未占据原子共振、近藤效应和自旋翻转激发。这些特征取决于 Cu2N 薄膜内的结合位点，并且与 Cu(100) 上 Co 的相应光谱明显不同。
Scanning tunneling microscopy is used to characterize the electronic structure of 1 ML films of c(2×2)N∕Cu(100) (i.e., Cu2N). By varying nitrogen coverage, a variety of morphologies are prepared, including (1) isolated ∼25nm2 islands, (2) close-packed arrays of islands, and (3) quasicontinuous monolayer films. In all three regimes, the authors find that Cu2N acts as an insulator, with a band gap that exceeds 4eV. The insulating Cu2N films are used to control the coupling of adsorbed Co atoms to the Cu(100) surface electron density. Tunneling spectroscopy of Co on Cu2N reveals an unoccupied atomic resonance, Kondo effect, and spin-flip excitation. These features depend on binding site within the Cu2N film, and are distinctly different than corresponding spectra for Co on Cu(100).