30 T scanning tunnelling microscope in a hybrid magnet with essentially non-metallic design

Wenjie Meng; Kesen Zhao; Jihao Wang; Jing Zhang; Qiyuan Feng; Ze Wang; Tao Geng; Tengfei Guo; Yubin Hou; Li Pi; Yalin Lu; Qingyou Lu

doi:10.1016/j.ultramic.2020.112975

30 T scanning tunnelling microscope in a hybrid magnet with essentially non-metallic design

Ultramicroscopy. 2020 May:212:112975. doi: 10.1016/j.ultramic.2020.112975. Epub 2020 Mar 12.

Authors

Wenjie Meng¹, Kesen Zhao¹, Jihao Wang¹, Jing Zhang¹, Qiyuan Feng¹, Ze Wang¹, Tao Geng¹, Tengfei Guo¹, Yubin Hou², Li Pi³, Yalin Lu⁴, Qingyou Lu⁵

Affiliations

¹ Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
² Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, Chinese Academy of Sciences, Hefei, Anhui 230031, China. Electronic address: ybhou@hmfl.ac.cn.
³ Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, Chinese Academy of Sciences, Hefei, Anhui 230031, China; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
⁴ Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China; Hefei Science Center, Chinese Academy of Sciences, Hefei 230031, China.
⁵ Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory and High Magnetic Field Laboratory of Anhui Province, Chinese Academy of Sciences, Hefei, Anhui 230031, China; Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, China; Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China; Hefei Science Center, Chinese Academy of Sciences, Hefei 230031, China. Electronic address: qxl@ustc.edu.cn.

PMID: 32278228
DOI: 10.1016/j.ultramic.2020.112975

Abstract

We report on the construction and performance of the first hybrid resistive-superconducting magnet (HM) based scanning tunnelling microscope (STM) above 30 T. This custom-design HM-STM features a novel design of the STM head unit, whose tip-sample approach is implemented using a slender piezoelectric tube (PZT). The scanner shares part of PZT by fixing a sapphire frame onto the front quarter of PZT to construct a compact tip-sample loop, realising an outer diameter of 8.8 mm, which makes it compatible with a narrow sample space. Its main components are made of non-metallic materials of sapphire, which allows it to be immune from eddy currents and to operate under the condition of strong magnetic field fluctuation from a hybrid magnet, as well as cryogen-free cryocooler magnet systems. To analyse the stiffness of the STM head unit, the eigenfrequencies with 11 kHz and 12 kHz in bending modes, 25 kHz in a torsional mode, and 67 kHz in a longitudinal mode were simulated by finite element analysis; also, the drifting rates of the STM in ambient conditions in the X-Y plane and Z direction were measured at 25.5 and 38.2 pm/min, respectively. We present the first atomic images in magnetic fields up to 30.1 T in an HM. The raw data show the stable and distinguished performance while ramping up to maximum fields, indicating the new device's potential capability of operating in the future 45T-hybrid magnet and hundred-field pulsed magnet. Meanwhile, our compact and concentric cylindrical STM insert can operate in the low-temperature tubular sample space housed by the HM bore to develop low-temperature and extreme high-magnetic field STM.

Keywords: 30.1 T atomic imaging; Hybrid magnet; Hybrid magnet scanning tunnelling microscope; Narrow design STM head unit; Non-metallic stm head unit.