Yang Zechao, Gura Leonard, Kalaß Florian, Marschalik Patrik, Brinker Matthias, Kirstaedter William, Hartmann Jens, Thielsch Gero, Junkes Heinz, Heyde Markus, Freund Hans-Joachim
Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
Rev Sci Instrum. 2022 May 1;93(5):053704. doi: 10.1063/5.0079868.
We present the design and development of a variable-temperature high-speed scanning tunneling microscope (STM). The setup consists of a two-chamber ultra-high vacuum system, including a preparation and a main chamber. The preparation chamber is equipped with standard preparation tools for sample cleaning and film growth. The main chamber hosts the STM that is located within a continuous flow cryostat for counter-cooling during high-temperature measurements. The microscope body is compact, rigid, and highly symmetric to ensure vibrational stability and low thermal drift. We designed a hybrid scanner made of two independent tube piezos for slow and fast scanning, respectively. A commercial STM controller is used for slow scanning, while a high-speed Versa Module Eurocard bus system controls fast scanning. Here, we implement non-conventional spiral geometries for high-speed scanning, which consist of smooth sine and cosine signals created by an arbitrary waveform generator. The tip scans in a quasi-constant height mode, where the logarithm of the tunneling current signal can be regarded as roughly proportional to the surface topography. Scan control and data acquisition have been programmed in the experimental physics and industrial control system framework. With the spiral scans, we atomically resolved diffusion processes of oxygen atoms on the Ru(0001) surface and achieved a time resolution of 8.3 ms per frame at different temperatures. Variable-temperature measurements reveal an influence of the temperature on the oxygen diffusion rate.
我们展示了一种可变温度高速扫描隧道显微镜（STM）的设计与开发。该装置由一个双腔超高真空系统组成，包括一个制备腔和一个主腔。制备腔配备有用于样品清洁和薄膜生长的标准制备工具。主腔内放置着STM，它位于一个连续流低温恒温器内，用于在高温测量期间进行反向冷却。显微镜主体紧凑、坚固且高度对称，以确保振动稳定性和低热漂移。我们设计了一种混合扫描器，由两个分别用于慢速和快速扫描的独立管式压电陶瓷组成。使用商业STM控制器进行慢速扫描，而高速Versa模块欧洲卡总线系统控制快速扫描。在这里，我们为高速扫描实现了非常规的螺旋几何形状，它由任意波形发生器产生的平滑正弦和余弦信号组成。针尖在准恒高模式下扫描，其中隧道电流信号的对数可大致视为与表面形貌成比例。扫描控制和数据采集已在实验物理和工业控制系统框架中进行了编程。通过螺旋扫描，我们在原子尺度上解析了氧原子在Ru(0001)表面的扩散过程，并在不同温度下实现了每帧8.3毫秒的时间分辨率。可变温度测量揭示了温度对氧扩散速率的影响。
