<br>Bi(111) 的表面改性和随后的费米密度增强,The Journal of Physical Chemistry C

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Bi(111) 的表面改性和随后的费米密度增强
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2021-03-05 , DOI: 10.1021/acs.jpcc.0c07345
Kuanysh Zhussupbekov ₁ , Killian Walshe ₁ , Brian Walls ₁ , Andrei Ionov ₂ , Sergei I Bozhko _{1,

2} , Andrei Ksenz ₂ , Rais N Mozhchil ₂ , Ainur Zhussupbekova ₁ , Karsten Fleischer _{1,

3} , Samuel Berman ₁ , Ivan Zhilyaev ₄ , David D O'Regan _{1,

5} , Igor V Shvets ₁

Affiliation

Bi(111) 表面引入的缺陷打破了平移对称性并局部改变了表面态。我们对 Bi(111) 表面的二维缺陷及其引起的状态进行了理论和实验研究。通过低能电子衍射 (LEED)、X 射线光电子能谱、紫外光电子能谱 (UPS) 和扫描技术研究在低温 (110 K) 超高真空 (UHV) 中裂解的 Bi 晶体以及由此产生的离子蚀刻表面隧道显微镜 (STM) 以及光谱 (STS) 技术与密度泛函理论 (DFT) 计算相结合。裂开 Bi(111) 的 STS 测量表明，与原子平坦平台相比，常见的双层阶梯边缘在费米能级周围具有较低的态密度 (DOS)。离子轰击后，Bi(111) 表面在 110 和 300 K 下均显示出异常行为：LEED 观察到表面周期性，STM 观察到双层台阶边缘和能量上不利的单层台阶数量显着增加。 UPS 测量和 Kohn-Sham DOS 证明，新暴露的单层台阶和 A 型双层台阶边缘导致表面费米密度增加。这些状态在特高压条件下似乎是热力学稳定的。

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Surface Modification and Subsequent Fermi Density Enhancement of Bi(111)

Defects introduced to the surface of Bi(111) break the translational symmetry and modify the surface states locally. We present a theoretical and experimental study of the 2D defects on the surface of Bi(111) and the states that they induce. Bi crystals cleaved in ultrahigh vacuum (UHV) at low temperature (110 K) and the resulting ion-etched surface are investigated by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and scanning tunneling microscopy (STM) as well as spectroscopy (STS) techniques in combination with density functional theory (DFT) calculations. STS measurements of cleaved Bi(111) reveal that a commonly observed bilayer step edge has a lower density of states (DOS) around the Fermi level as compared to the atomic-flat terrace. Following ion bombardment, the Bi(111) surface reveals anomalous behavior at both 110 and 300 K: Surface periodicity is observed by LEED, and a significant increase in the number of bilayer step edges and energetically unfavorable monolayer steps is observed by STM. It is suggested that the newly exposed monolayer steps and the type A bilayer step edges result in an increase to the surface Fermi density as evidenced by UPS measurements and the Kohn–Sham DOS. These states appear to be thermodynamically stable under UHV conditions.

更新日期：2021-03-18

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