A variable-temperature scanning tunneling microscope operated in a continuous flow cryostat
A variable-temperature scanning tunneling microscope operated in a continuous flow cryostat
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在连续流低温恒温器中运行的变温扫描隧道显微镜
DOI：
10.1063/1.5118676
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发表时间：
2019-09-01
影响因子：
1.6
通讯作者：
Lu, Qingyou
中科院分区：
文献类型：
--
作者：
Wang, Jihao;Hou, Yubin;Lu, Qingyou
我们提出了一种连续流低温恒温扫描隧道显微镜（STM），它可以在4.9 K到300 K的温度范围内工作。一个20毫米孔径的可变温度插入器安装在低温恒温器中。采用氦交换气体冷却，STM头的基温为4.9 K。采用一种新型的氧化锆结构设计，将STM头的外径减小到9.2 mm。STM头的高密实度和刚性使其对振动不太敏感，有助于尖端样品结的高稳定性。在4.9 K时，STM在X-Y平面和Z方向的漂移速率分别为1.96和3.05 pm/min。在不使用外部振动隔离的情况下，通过石墨和NbSe2的原子分辨成像证明了STM的性能。在临界温度附近对NbSe2的dI/dV谱进行了解析，说明了超导隙的形成过程与温度的关系。该STM是超高真空和强磁场兼容，使其有希望在极端条件下直接应用，包括水冷磁铁和混合磁铁。
We present a continuous flow cryostat scanning tunneling microscope (STM) which can be operated at temperatures between 4.9 K and 300 K. A variable temperature insert with 20 mm aperture is installed in the cryostat. A base temperature of 4.9 K at the STM head was achieved with helium exchange gas cooling. By using a novel design of zirconia structure, the size of the STM head was minimized to 9.2 mm in outer diameter. The high compactness and rigidity of the STM head make it less sensitive to vibrations, contributing to the high stability of the tip-sample junction. The drifting rates of the STM at 4.9 K in the X-Y plane and Z direction are 1.96 and 3.05 pm/min, respectively. The performance of the STM was demonstrated by atomically resolved imaging of graphite and NbSe2 without using external vibrational isolation. Furthermore, the dI/dV spectra of NbSe2 were resolved near its critical temperature, illustrating the formation process of the superconducting gap as a function of temperature. This STM is ultrahigh vacuum and strong magnetic field compatible, making it promising for direct application in the extreme conditions involving water-cooled magnets and hybrid magnets.