分类: 工程与技术科学 >> 物理学相关工程与技术 分类: 工程与技术科学 >> 仪器仪表技术 分类: 电子与通信技术 >> 电子技术 分类: 物理学 >> 交叉学科物理及相关领域的科学与技术 提交时间: 2024-05-06
摘要: 本文提出了一种用于低温扫描隧道显微镜(CryoSTM)的跨阻放大器(TIA)设计方案。在CryoSTM中带有尖端样品成分的TIA称为CryoSTM-TIA。该CryoSTM-TIA的跨阻增益在1Gohm,而其带宽大于300kHz。所提出的CryoSTM-TIA的独特特点是其前置放大器由单个低温高电子迁移率晶体管(HEMT)制成,因此在100kHz时仪器等效输入噪声电流功率谱密度低于4(fA)2/Hz。此外,应用“偏置冷却法”可用于原位控制HEMT掺杂区冻结DX-中心的密度,改变其结构以降低器件噪声。利用该仪器,可以进行高能量分辨率的快速扫描隧道光谱测量。并且,它能够测量各种量子系统在原子尺度上的扫描隧道散粒噪声谱(STSNS),即使散粒噪声非常低。它为通过测量STSNS来研究新的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。
分类: 物理学 >> 凝聚态:电子结构、电、磁和光学性质 提交时间: 2021-12-18
摘要: True random number generator (TRNG) is an important component for modern information security technologies. Among the candidates, TRNG with spin-orbit torque (SOT)-induced probabilistic magnetization switching is competitive for its advantages in anti-radiation, unlimited endurance, robust stability, and broad temperature range. However, realization of a SOT-TRNG requires intensive understanding of the magnetic dynamic process under a spin-orbit current. Here, we performed micromagnetic simulation of the SOT-induced probabilistic magnetization switching by using Mumax 3. Without thermal noise, identical magnetic moment precessions were found between repeated simulation cycles, resulting in deterministic magnetization switching. When thermal noises were taken into account, stochastic precession trails and thereby probabilistic magnetization switching were finally obtained. Our results suggest the Mumax 3 to be a practical tool for simulating the probabilistic magnetization switching behavior of a SOT-TRNG, as well as highlighting the crucial role of thermal noise during the during the simulation.