Liang Ying-Xin
Beijing Academy of Quantum Information Sciences, Haidian 100193, Beijing, China; Coll Phys & Elect Engn, Anyang Normal University, Anyang, 455000, Henan, China.
Ultramicroscopy. 2024 Dec;267:114051. doi: 10.1016/j.ultramic.2024.114051. Epub 2024 Sep 19.
In this work, a design of transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. TIA with the tip-sample component in CryoSTM is called as CryoSTM-TIA. With transimpedance gain of 1 GΩ, the bandwidth of the CryoSTM-TIA is larger than 200 kHz. The distinctive feature of the proposed CryoSTM-TIA is that its pre-amplifier is made of a single cryogenic high electron mobility transistor (HEMT), so the apparatus equivalent input noise current power spectral density at 100 kHz is lower than 6 (fA)/Hz. In addition, "bias-cooling method" can be used to in-situ control the density of the frozen DX centers in the HEMT doping area, changing its structure to reduce the device noises. With this apparatus, fast scanning tunneling spectra measurements with high-energy-resolution are capable to be performed. And, it is capable to measure scanning tunneling shot noise spectra (STSNS) at the atomic scale for various quantum systems, even if the shot noise is very low. It provides a powerful tool to investigate novel quantum states by measuring STSNS, such as detecting the existence of Majorana bound states in the topological quantum systems.
在这项工作中，提出了一种用于低温扫描隧道显微镜（CryoSTM）的跨阻放大器（TIA）设计。在CryoSTM中带有针尖 - 样品组件的TIA被称为CryoSTM - TIA。CryoSTM - TIA的跨阻增益为1 GΩ，带宽大于200 kHz。所提出的CryoSTM - TIA的独特之处在于其前置放大器由单个低温高电子迁移率晶体管（HEMT）制成，因此该装置在100 kHz时的等效输入噪声电流功率谱密度低于6（fA）/Hz。此外，“偏置冷却方法”可用于原位控制HEMT掺杂区域中冻结的DX中心的密度，改变其结构以降低器件噪声。使用该装置能够进行具有高能量分辨率的快速扫描隧道谱测量。并且，即使散粒噪声非常低，它也能够在原子尺度上测量各种量子系统的扫描隧道散粒噪声谱（STSNS）。它为通过测量STSNS研究新型量子态提供了一个强大的工具，例如检测拓扑量子系统中马约拉纳束缚态的存在。
