High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
University of Science and Technology of China, Hefei, Anhui 230026, China.
Rev Sci Instrum. 2023 Mar 1;94(3):033705. doi: 10.1063/5.0121761.
Scanning tunneling microscopes (STMs) that work in ultra-high vacuum and low temperatures are commonly used in condensed matter physics, but an STM that works in a high magnetic field to image chemical molecules and active biomolecules in solution has never been reported. Here, we present a liquid-phase STM for use in a 10 T cryogen-free superconducting magnet. The STM head is mainly constructed with two piezoelectric tubes. A large piezoelectric tube is fixed at the bottom of a tantalum frame to perform large-area imaging. A small piezoelectric tube mounted at the free end of the large one performs high-precision imaging. The imaging area of the large piezoelectric tube is four times that of the small one. The high compactness and rigidity of the STM head make it functional in a cryogen-free superconducting magnet with huge vibrations. The performance of our homebuilt STM was demonstrated by the high-quality, atomic-resolution images of a graphite surface, as well as the low drift rates in the X-Y plane and Z direction. Furthermore, we successfully obtained atomic-resolution images of graphite in solution conditions while sweeping the field from 0 to 10 T, illustrating the new STM's immunity to magnetic fields. The sub-molecular images of active antibodies and plasmid DNA in solution conditions show the device's capability of imaging biomolecules. Our STM is suitable for studying chemical molecules and active biomolecules in high magnetic fields.
扫描隧道显微镜（STM）在超高真空和低温环境下工作，常用于凝聚态物理研究，但在磁场环境下对溶液中的化学分子和生物活性分子进行成像的 STM 还从未有过报道。在这里，我们展示了一种可在 10T 液氦免挥发磁体中使用的液相 STM。STM 探头主要由两个压电管组成。一个大的压电管固定在钽制框架底部，用于大面积成像。一个小的压电管安装在大压电管的自由端，用于进行高精度成像。大压电管的成像面积是小压电管的四倍。STM 探头的高紧凑性和刚性使其可在具有巨大振动的液氦免挥发磁体中工作。我们自制的 STM 的性能通过石墨表面的高质量原子分辨率图像以及 X-Y 平面和 Z 方向的低漂移率得到了证明。此外，我们成功地在磁场从 0 到 10T 的范围内获得了溶液中石墨的原子分辨率图像，这表明新 STM 对磁场具有免疫性。溶液条件下活性抗体和质粒 DNA 的亚分子图像显示了该设备对生物分子成像的能力。我们的 STM 适用于在强磁场中研究化学分子和生物活性分子。
