Colliding quasiparticles to reconstruct their effective Hamiltonians

碰撞准粒子重建其有效哈密顿量

• 批准号: 2004995
• 负责人: Mark Sherwin
• 金额: $ 57万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004995&HistoricalAwards=false
• 关键词: Colliding; quasiparticles; reconstruct; their; effective

Non-technical abstract: Our national competitiveness relies on our ability to make information technology faster, more energy efficient, more compact, and more affordable. Such innovation requires the discovery and implementation of new methods to characterize and then optimize the responses of materials to electricity and light. To fully understand how electrical charges move in the extremely strong and rapidly-varying electric fields that pervade modern electronics and optics, one needs to know quantities called Bloch wavefunctions, which were derived mathematically more than 90 years ago but have resisted experimental determination. The PI and his team have recently developed a robust method to reconstruct Bloch wavefunctions from experimental data which was demonstrated on a crystalline solid. The project supports reconstruction of Bloch wavefunctions in a several semiconductors that are of current scientific and technological importance. The graduate student researchers supported by this project receive broad and deep training in experimental condensed matter physics, and in turn mentor undergraduate researchers, inspire K-12 students by giving them hands-on experience with simple electrical circuits and, upon graduation are positioned for leadership in technical fields crucial to national competitiveness. Technical abstract: For many problems in modern condensed matter physics, it is important to know both the energy eigenvalues of a quasiparticle effective Hamiltonian, as well as its Bloch wavefunctions, from which the Berry curvature can be calculated. By integrating the Berry curvature over the Brillouin zone, materials can be classified topologically. Angle-Resolved Photoemission Spectroscopy enables one to measure the band structure of many materials. However, the Bloch wavefunctions and Berry curvature, which are defined at each point in quasi-momentum space, are extremely difficult to measure. This project exploits a unique opportunity to reconstruct the effective Hamiltonian of quasiparticles in semiconductors that is enabled by the phenomenon of high-order sideband generation (HSG). HSG can be thought of as a three-step process in which (1) a weak probe laser creates electron-hole pairs, (2) a strong terahertz-frequency laser adiabatically accelerates the electrons and holes first away from and then back towards each other, and (3) the electrons and holes collide and recombine, emitting sidebands that carry off the kinetic energy associated with the collision, and on whose polarization is imprinted the Berry curvature of the bands through which the electrons and holes have been accelerated. In this project, the parameters of the effective Hamiltonian that governs quasiparticle dynamics in GaAs (including the effects of strain), GeS (a layered semiconductor), and other semiconductors will be reconstructed by comparing the calculated and measured matrices that relate the polarization of sidebands to the polarization of the probe laser that excited them.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.

非技术摘要：我们的国家竞争力依赖于我们使信息技术更快、更节能、更紧凑、更便宜的能力。这种创新需要发现和实施新方法来表征并优化材料对电和光的响应。为了充分了解电荷如何在现代电子学和光学领域普遍存在的极强且快速变化的电场中移动，我们需要了解称为布洛赫波函数的量，该量是 90 多年前通过数学推导出来的，但一直无法通过实验确定。 PI 和他的团队最近开发了一种强大的方法，可以根据实验数据重建布洛赫波函数，并在晶体固体上进行了演示。该项目支持在多种半导体中重建布洛赫波函数，这些半导体在当前的科学和技术方面具有重要意义。该项目支持的研究生研究人员接受了实验凝聚态物理方面广泛而深入的培训，反过来又指导本科生研究人员，通过为 K-12 学生提供简单电路的实践经验来激励他们，并在毕业后担任领导职务在对国家竞争力至关重要的技术领域。技术摘要：对于现代凝聚态物理中的许多问题，了解准粒子有效哈密顿量的能量本征值及其布洛赫波函数非常重要，从中可以计算贝里曲率。通过对布里渊区上的贝里曲率进行积分，可以对材料进行拓扑分类。角分辨光电发射光谱使人们能够测量许多材料的能带结构。然而，在准动量空间中的每个点定义的布洛赫波函数和贝里曲率极难测量。该项目利用了一个独特的机会来重建半导体中准粒子的有效哈密顿量，这是通过高阶边带生成（HSG）现象实现的。 HSG 可以被认为是一个三步过程，其中 (1) 弱探测激光产生电子空穴对，(2) 强太赫兹频率激光绝热加速电子和空穴，首先远离彼此，然后返回彼此，（3）电子和空穴碰撞并重新结合，发射边带，携带与碰撞相关的动能，并且其极化上印有电子和空穴所通过的能带的贝里曲率。加速。在该项目中，将通过比较与边带偏振相关的计算和测量矩阵来重建控制 GaAs（包括应变影响）、GeS（层状半导体）和其他半导体中准粒子动力学的有效哈密顿量参数该奖项反映了 NSF 的法定使命，并且通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Explicit formula for high-order sideband polarization by extreme tailoring of Feynman path integrals

通过费曼路径积分的极端剪裁的高阶边带偏振的显式公式

• DOI: 10.1103/physrevb.107.174308
• 发表时间: 2023-02-06
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Qile Wu;M. Sherwin
• 通讯作者: M. Sherwin

Reconstruction of Bloch wavefunctions of holes in a semiconductor

半导体中空穴布洛赫波函数的重建

• DOI: 10.1038/s41586-021-03940-2
• 发表时间: 2021-11
• 期刊: Nature
• 影响因子: 64.8
• 作者: Costello, J. B.;O’Hara, S. D.;Wu, Q.;Valovcin, D. C.;Pfeiffer, L. N.;West, K. W.;Sherwin, M. S.
• 通讯作者: Sherwin, M. S.