Nanoscale Microwave Sources Based on Planar Spin Oscillators for Integrating Wireless Communications on the Computing Platform

基于平面自旋振荡器的纳米级微波源，用于在计算平台上集成无线通信

• 批准号: EP/E001688/1
• 负责人: Christopher Marrows
• 金额: $ 3.49万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE001688%2F1
• 关键词: Nanoscale; Microwave; Sources; Based; Planar

Over the past 30 years, the increase in performance of integrated circuits and the reduction in the cost of computers have been achieved through the miniaturisation of transistors and their denser integration on a semiconductor chip. This scaling down has been accompanied by a reduction in the area and pitch of interconnects to the point where today circuit speed is limited, not by transistors, but by the severe losses experienced when electrical signals travel through metal wires at high frequencies. To carry on enhancing system performance, semiconductor industry roadmaps envision replacing metal wires with wireless interconnects. Broadcasting signals in free space promises extremely high-speed communication channels that transmit data without attenuation and adaptive wireless networks that are secure and tolerant to hardware defects. Integrating communication capabilities at the chip level accelerates the convergence of computing and communication systems to ultimately enable all computers to communicate and all communication devices to compute. To implement this vision physicists must now conceive novel emitter and receiver devices directed towards making inter/intra-chip interconnects.We aim to generate microwaves by a process of 'inverse electron spin resonance' that we will demonstrate in hybrid semiconductor/ferromagnetic structures. The stray magnetic field emanating from ultra-small magnetic elements will thread a sheet of free electrons trapped at the interface between two semiconductors. We will apply an electrical current to this system to activate electron oscillations in the microscopically inhomogeneous magnetic field. An electron carries a tiny magnetic moment that aligns with a magnetic field in the same way as a compass needle aligns with the Earth magnetic field. The electron magnetic moment is therefore sensitive to the stray magnetic field emanating from a nano-magnet as the electron oscillates underneath it. The stray magnetic field vector component oriented in the plane of the semiconductor interface has constant amplitude and causes the electron magnetic moment to gyrate at constant speed, with the same precession motion as a spinning top. By contrast, the magnetic field vector component perpendicular to the plane oscillates at the frequency of the electron oscillator. When the precession frequency equals the oscillator frequency, the electron magnetic moment resonantly radiates microwave energy.We will combine precision lithography with thin film deposition techniques at the University of Bath to fabricate hybrid semiconductor/ferromagnetic structures hosting electron oscillators. We will activate these oscillators by applying a direct current to the semiconductor wire and will measure microwave emission spectra as a function of experimental and structural parameters. The quantum mechanical coupling of the oscillating magnetic moment to the electromagnetic field will give complete spectral information on the oscillator dynamics and will allow us to demonstrate a multiple frequency source broadcasting several communication channels simultaneously. We will investigate weakly coupled electron oscillators to enhance the coherence and power of microwaves at room temperature. We will broadcast wireless signals through airwaves or in a guided medium between two hybrid devices fabricated on the same semiconductor chip. Nanoscale wireless networks enhance the speed, security and cost-efficiency of computers, they facilitate communications with remote sensors that are increasingly used in industrial processes, health monitoring and military applications. A very attractive aspect of our proposal is that the Physics is material independent. As a result, our conclusions will hold for two-dimensional electron systems formed in carbon sheets (graphene), semiconductor quantum wells or the surface of liquid helium when subjected to the above electric and magnetic fields.

过去30年来，集成电路性能的提高和计算机成本的降低是通过晶体管的小型化及其在半导体芯片上的更密集集成来实现的。这种尺寸缩小伴随着互连面积和间距的减小，以至于当今电路速度受到限制的不是晶体管，而是电信号在高频下通过金属线传输时所经历的严重损耗。为了继续增强系统性能，半导体行业路线图设想用无线互连取代金属线。在自由空间中广播信号有望实现无衰减传输数据的极高速通信通道，以及安全且能够容忍硬件缺陷的自适应无线网络。在芯片级集成通信能力可以加速计算和通信系统的融合，最终使所有计算机都能通信，所有通信设备都能计算。为了实现这一愿景，物理学家现在必须构思新颖的发射器和接收器设备，旨在制造芯片间/芯片内互连。我们的目标是通过“逆电子自旋共振”过程产生微波，我们将在混合半导体/铁磁结构中演示这一过程。超小型磁性元件发出的杂散磁场将穿过被困在两个半导体之间的界面处的一片自由电子。我们将向该系统施加电流，以激活微观不均匀磁场中的电子振荡。电子带有微小的磁矩，它与磁场对齐，就像指南针与地球磁场对齐一样。因此，当电子在纳米磁体下方振荡时，电子磁矩对纳米磁体发出的杂散磁场敏感。定向在半导体界面平面上的杂散磁场矢量分量具有恒定的幅度，并导致电子磁矩以恒定的速度旋转，其进动运动与陀螺相同。相反，垂直于平面的磁场矢量分量以电子振荡器的频率振荡。当进动频率等于振荡器频率时，电子磁矩共振辐射微波能量。我们将精密光刻与巴斯大学的薄膜沉积技术相结合，制造承载电子振荡器的混合半导体/铁磁结构。我们将通过向半导体线施加直流电来激活这些振荡器，并将测量微波发射光谱作为实验和结构参数的函数。振荡磁矩与电磁场的量子力学耦合将提供有关振荡器动力学的完整光谱信息，并使我们能够演示同时广播多个通信通道的多频率源。我们将研究弱耦合电子振荡器，以增强室温下微波的相干性和功率。我们将通过无线电波或在同一半导体芯片上制造的两个混合设备之间的引导介质来广播无线信号。纳米级无线网络提高了计算机的速度、安全性和成本效率，它们促进了与越来越多地用于工业过程、健康监测和军事应用的远程传感器的通信。我们提案的一个非常有吸引力的方面是物理学是与材料无关的。因此，我们的结论对于在碳片（石墨烯）、半导体量子阱或液氦表面形成的二维电子系统在上述电场和磁场作用下成立。