An ultracompact scanning tunneling microscope within a Φ 10 piezo tube in a 20 T superconducting magnet

Min Zhang; Jihao Wang; Wenjie Meng; Jing Zhang; Qiyuan Feng; Ze Wang; Yalin Lu; Yubin Hou; Qingyou Lu

doi:10.1063/5.0191662

An ultracompact scanning tunneling microscope within a Φ 10 piezo tube in a 20 T superconducting magnet

Rev Sci Instrum. 2024 Mar 1;95(3):033704. doi: 10.1063/5.0191662.

Authors

Min Zhang^{1

2

3}, Jihao Wang^{2

3}, Wenjie Meng^{2

3}, Jing Zhang^{2

3}, Qiyuan Feng^{2

3}, Ze Wang^{2

3}, Yalin Lu^{1

4}, Yubin Hou^{2

3}, Qingyou Lu^{1

2

3

4}

Affiliations

¹ University of Science and Technology of China, Hefei, Anhui 230026, China.
² Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
³ High Magnetic Field Laboratory of Anhui Province, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.
⁴ Anhui Laboratory of Advanced Photon Science and Technology, University of Science and Technology of China, Hefei 230026, China.

PMID: 38546294
DOI: 10.1063/5.0191662

Abstract

Low-temperature scanning tunneling microscopy and spectroscopy (STM/S) help to better understand the fundamental physics of condensed matter. We present an ultracompact STM within a Φ 10 piezo tube in a 20 T superconducting magnet. The carefully cut piezo tube contains the STM's coarse-positioning assembly. Loading an STM tip-sample mechanical loop into the piezo tube with special cut openings enables an ultracompact pencil-size dimension down to Φ 10 mm, in which fine-machined nonmagnetic parts are assembled to enable slide-stick motion and xyz-scanning procedures. The small size leads to a higher resonant frequency, a typical feature of a rigid STM instrument, increasing its vibration immunity. Scanning by moving the sample while keeping the tip stationary improves the stability of the tip-sample junction compared to moving the tip. Taking advantage of its high-field compatibility and rigid design, our STM captures the atomically resolved topography of highly oriented pyrolytic graphite (HOPG) at 1.5 K and in magnetic fields up to 17 T. The topography of graphene lattice and graphite is simultaneously recorded on an atomic terrace of HOPG, unveiling a modified local charge density at a surface defect. The superconducting energy gaps of layered type-II superconductors NbSe2 and PdBi2 are well resolved through dI/dV tunneling spectra at sub-2 K. Our unique STM is highly suitable for potential STM/S applications in world-class high-field facilities where the strong magnetic field can exceed 30 T.