Kaku Shigeru, Yoshino Junji
Department of Physics, Tokyo Institute of Technology, Tokyo, 152-8550, Japan.
Small. 2020 Aug;16(32):e2002296. doi: 10.1002/smll.202002296. Epub 2020 Jul 2.
The temperature-dependent tip-induced-motion of a Ga adatom on a GaAs (110) surface is experimentally demonstrated using scanning tunneling microscopy (STM). The surface adsorption energy profile obtained by first-principle electronic structure calculations reveals that the origin of the Ga motion observed at 78 K is attributable to the tip-induced Ga adatom hopping between the most stable potential minima among the three local minima, whereas that observed at 4.2 K is attributable to the tip-induced hopping and sliding motions through the next stable minima as well as the most stable minima. Furthermore, it is shown that a slight progressive modification of the adatom motion observed only at 4.2 K resulting from repeated STM line scans is consistent with the overall picture taking account of the heating of the adatom owing to the tip current.
利用扫描隧道显微镜（STM）通过实验证明了在GaAs（110）表面上，温度依赖的Ga吸附原子的针尖诱导运动。通过第一性原理电子结构计算获得的表面吸附能分布表明，在78 K时观察到的Ga运动起源于针尖诱导的Ga吸附原子在三个局部极小值中最稳定的势阱之间跳跃，而在4.2 K时观察到的运动则归因于针尖诱导的通过次稳定极小值以及最稳定极小值的跳跃和滑动运动。此外，结果表明，仅在4.2 K时观察到的由于重复STM线扫描导致的吸附原子运动的轻微渐进变化，与考虑到由于针尖电流导致吸附原子加热的整体情况是一致的。
