Electron states confined within nano-steps on metal surfaces
Electron states confined within nano-steps on metal surfaces
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DOI：
10.1088/0953-8984/23/4/045008
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发表时间：
2011-02-02
影响因子：
2.7
通讯作者：
Tamura, Akira
中科院分区：
文献类型：
--
作者：
Mitsuoka, Shigenori;Tamura, Akira
为了阐明限制在金属表面上的步骤中的电子状态，我们证明了一个新的观点，即贵金属表面上的线性步骤可以被视为由δ函数组成的偶极势。对于一个受两对偶极势约束的电子，我们导出了准定态本征态，其本征能是导致电子寿命的复数.为了得到台阶表面的局域态密度（LDOS）、扫描隧道显微镜（STM）图像和扫描隧道谱（STS），我们引入了寿命效应，并应用Selloni等人推导的STM电流表达式，阐明了LDOS与STM电流之间的关系（1985 Phys. Rev. B 31 2602）。虽然，在以前的研究中，法布里-珀罗干涉机制已被用来解释电子状态限制在两个步骤，它需要四个拟合参数，相比之下，我们的方法需要一个拟合参数，指定的高度的δ函数。对LDOS图像、地形图像和STS图像的计算结果表明，无论是电子停留在两个台阶之间的平台上，还是在台阶外的宽平台上，计算结果都与实验结果一致，验证了模型的有效性.
To elucidate electron states confined within steps on metal surfaces, we demonstrated a new point of view that a linear step on a noble metal surface can be treated as a dipole potential composed of delta functions. For an electron confined by two pairs of dipole potentials, we derived quasi-stationary eigenstates whose eigenenergies are complex numbers which lead to the lifetime of the electron. To derive the local density of states (LDOS), scanning tunneling microscopy (STM) images and scanning tunneling spectra (STS) for stepped surfaces, we incorporated the lifetime effect on them and clarified the relation between the LDOS and the STM current by applying the expression for the STM current derived by Selloni et al (1985 Phys. Rev. B 31 2602). Although, in previous studies, the Fabry-Perot interference mechanism has been used to explain electron states confined within two steps, it requires four fitting parameters, in contrast our method requires one fitting parameter which specifies the height of the delta functions. Our results for LDOS images, topographical images and STS are consistent with experimental ones for both the cases where electrons stay on a terrace confined by two steps and on a wide terrace outside the step, which confirms the validity of our model.