Bloch wave interferometry in semiconductors and correlated insulators

半导体和相关绝缘体中的布洛赫波干涉测量

• 批准号: 2333941
• 负责人: Mark Sherwin
• 金额: $ 73.03万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-15 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2333941&HistoricalAwards=false
• 关键词: Bloch; wave; interferometry; semiconductors; correlated

Nontechnical description:Meeting society’s future demands for information technology requires ever-increasing control over semiconducting materials, from which electronics are made, and light, which transmits vast quantities of information at continually-increasing speeds. Quantum mechanics tells us that electrons in semiconductors should behave like waves. A detailed understanding of these electronic waves is required to engineer the next generations of electronic and optical devices. Recently, using a powerful, building-sized laser to rapidly accelerate charges in a semiconductor and smash them back together before they can collide with anything else, the principle investigator’s group has been able to observe two kinds of accelerated electronic waves interfering with one another, analogous to the interaction of ripples from two stones thrown into a pond. From the pattern of the interference, the principle investigator’s group has been able, for the first time, to reconstruct directly from experimental data the mathematical form of interfering electronic waves in a semiconductor. In this project, the research team leverages the interference of electronic waves to develop a method to precisely measure important parameters that govern both the motion of charges in and the absorption and emission of light from semiconductors. The research is carried out by graduate and undergraduate student researchers who, in the process, get rigorous training in semiconductor physics, optics, and, most importantly, solving hard problems that have never been solved before. With this training, these researchers will be well-positioned to contribute to developing future information technologies in industry, academia, or government. These researchers also participate in the PI’s popular educational outreach program that has, since 2005, brought attractive, engaging and robust "Questboards" to local community science nights for K-12 students to get hands-on experience with electrical circuits.Technical description:Interferometry is a powerful tool for measuring information encoded in waves of all sorts. Charged quasiparticles in solids have a wavelike character that is captured in their Bloch wavefunctions. In 2011, the principle investigator’s group reported the experimental discovery of high-order sideband generation, in which a semiconductor driven simultaneously by a weak near-infrared laser and a strong THz laser can emit many dozen near-infrared sidebands in a comb-like spectrum with comb teeth separated by an integer multiple of the THz frequency. Recently, the group reported that the polarizations of sidebands emitted from bulk gallium arsenide (GaAs) can be viewed as interferograms from a Michelson-like interferometer for Bloch waves, and calculated using a simple analytical model. This project uses quantitative Bloch-wave interferometry in three ways: (1) reconstruct the effective Hamiltonian, precise band gaps, and de-phasing processes of electron-hole pairs in bulk GaAs. This will open the door to much more precise electronic structure measurements in the technologically-critical direct-gap semiconductors; (2) measure anomalous displacements (transverse to the direction of the accelerating electric field) of holes in GaAs quantum wells caused by extremely large valence band Berry curvatures. This will be among the cleanest demonstrations of anomalous velocity—first predicted nearly 70 years ago—and may enable a direct measurement of the local Berry curvature of a band; (3) extend Bloch-wave interferometry to Mott insulators, beginning with the van der Waals antiferromagnet NiPS3, a promising candidate because of its extremely bright and narrow exciton, opening a new window into the electronic structure of strongly-correlated insulators.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述：满足社会未来对信息技术的需求需要不断加强对制造电子产品的半导体材料和以不断提高的速度传输大量信息的光的控制。量子力学告诉我们，半导体中的电子应该表现出行为。最近，需要对这些电子波进行详细了解，以设计下一代电子和光学设备，使用强大的、建筑物大小的激光器来快速加速半导体中的电荷并将其击碎。在它们与其他物体碰撞之前，首席研究员的小组已经能够观察到两种相互干扰的加速电子波，类似于扔进池塘的两块石头产生的涟漪的相互作用。研究人员的群原理首次能够直接根据实验数据重建半导体中干扰电子波的数学形式。在该项目中，研究团队利用电子波的干扰开发了一种精确测量的方法。控制两者的重要参数该研究由研究生和本科生研究人员进行，他们在此过程中接受了半导体物理、光学方面的严格培训，最重要的是，解决了半导体中的难题。通过这次培训，这些研究人员将能够为工业界、学术界或政府的未来信息技术的发展做出贡献。这些研究人员还参与了 PI 自 2005 年以来广受欢迎的教育推广计划。有吸引力、有吸引力且稳健为 K-12 学生提供当地社区科学之夜的“任务板”，让他们获得电路的实践经验。技术描述：干涉测量是一种强大的工具，用于测量固体中的带电准粒子具有波状特征的信息。 2011 年，首席研究员的团队报告了高阶边带生成的实验发现，其中半导体由弱近红外激光和强太赫兹激光器可以在梳状光谱中发射数十个近红外边带，梳齿间隔为太赫兹频率的整数倍。最近，该小组报告说，从块状砷化镓（GaAs）发射的边带的偏振可以。可以被视为布洛赫波类迈克尔逊干涉仪的干涉图，并使用简单的分析模型进行计算。该项目通过三种方式使用定量布洛赫波干涉测量： (1) 重建块状 GaAs 中电子-空穴对的有效哈密顿量、精确带隙和移相过程，这将为技术关键的直接带隙半导体中更精确的电子结构测量打开大门 (2) ) ) 测量由极大的价带贝里曲率引起的 GaAs 量子阱中空穴的反常位移（垂直于加速电场的方向），这将是反常速度的最清晰的演示之一。近 70 年前就预测过，并且可以直接测量能带的局部贝里曲率；(3) 将布洛赫波干涉测量扩展到莫特绝缘体，从范德瓦尔斯反铁磁体 NiPS3 开始，它是一个有前途的候选者，因为它极其明亮和窄激子，为强相关绝缘体的电子结构打开了新的窗口。该奖项反映了 NSF 的法定使命，并通过使用基金会的评估进行评估，认为值得支持智力价值和更广泛的影响审查标准。