Kuck Stefan, Wienhausen Jan, Hoffmann Germar, Wiesendanger Roland
Institute of Applied Physics, University of Hamburg, Hamburg 20355, Germany.
Rev Sci Instrum. 2008 Aug;79(8):083903. doi: 10.1063/1.2972971.
We describe and discuss the design of a variable-temperature scanning tunneling microscope (STM) system for the study of molecules at temperatures between 18 and 300 K in ultrahigh vacuum. The STM head is a refinement of a very rigid design developed and successfully operated in Hamburg. In the current version, the head is connected to a liquid helium flow cryostat, thereby reaching a base temperature of 18 K. To minimize the heat load on the STM head, a helium back flow cooled radiation shield is installed. The dimensions and the choice of materials are based on simulations of the heat dissipation. The STM is galvanically isolated from the vacuum chamber to minimize electronic noise and mechanically decoupled by means of springs and an eddy current damping stage. Additionally, the design of the STM head allows the deposition of several molecular materials onto the same cold sample surface. The operation of the STM in imaging mode is demonstrated for TPP/Cu(111) and FePCNaClCu(111). Spectroscopic capabilities of the system are shown for electronic states on NaClCu(111) and TPP/Cu(111).
我们描述并讨论了一种可变温度扫描隧道显微镜（STM）系统的设计，该系统用于在超高真空环境下研究温度在18至300 K之间的分子。STM探头是对在汉堡开发并成功运行的一种非常坚固的设计的改进。在当前版本中，探头连接到液氦流动低温恒温器，从而达到18 K的基础温度。为了使STM探头上的热负荷最小化，安装了氦气回流冷却辐射屏蔽。尺寸和材料的选择基于散热模拟。STM与真空腔进行电隔离以最小化电子噪声，并通过弹簧和涡流阻尼阶段进行机械解耦。此外，STM探头的设计允许将几种分子材料沉积到同一个低温样品表面上。展示了STM在成像模式下对TPP/Cu(111)和FePCNaClCu(111)的操作。展示了该系统对NaClCu(111)和TPP/Cu(111)上电子态的光谱分析能力。
