Driving Quantum Systems with Classical Fields

控制半导体器件中电子运动的能力是电子、光子学和声学的核心，这些都是基础科学领域，促进了能源、通信、传感、信息科学和安全方面的技术进步。电子是存在于每个原子中的非常小的粒子，它们遵守量子力学定律，这使得以高度可预测的方式与它们相互作用并控制它们的运动具有挑战性。这个项目背后的中心问题是，人们如何利用光和声这两种日常生活中常见的经典波来激发或驱动现代半导体设备中的电子。这些设备的大小只有几纳米，不到人类头发厚度的千分之一。由于设备尺寸小，不可避免的缺陷，理解光和声音如何与设备中的电子相互作用比在大得多的系统中回答同样的问题要困难得多，例如块状材料。然而，器件尺寸小也可能导致出现具有重大技术影响的引人注目的新现象。为此，将在该项目期间开发最先进的模拟软件，以分析纳米设备中的电子如何与经典光和声音相互作用。以实验为基准的微观理论和精确的模拟工具，例如将在该项目过程中开发的工具，对于在纳米尺度上加深对世界的理解以及预测新的现象和功能是非常宝贵的，所有这些都只需花费实验成本的一小部分。该项目将通过帮助设计新设备而使工业界和学术界的实验团体受益。这些代码将通过GitHub以开源的形式分发，以确保广泛使用。如何使用经典波，无论是电磁波还是声学波，来激励或驱动现代纳米结构中的量子电子系统？这个问题涉及电子学、光子学和声学，并产生了从能源到通信、传感、信息科学和安全的技术影响。答案需要深入了解纳米材料和纳米结构中电荷与光和声相互作用的物理过程，并且答案与其在块体材料中的模拟有很大的不同，因为这些系统的低维和小尺寸导致它们对边界和边缘、无序、周围材料的性质敏感，也可能导致显著的新的等离子体、极化子和激子现象的出现。为此，该项目的目标是开发和部署一种全面的建模方法，使用最先进的经典电磁波和弹性波的模拟技术，以及用于量子电子传输的高效密度矩阵技术，以便在纳米尺度上理解和利用光、声和电荷的相互作用。这项工作将被组织成两个冲刺，每个冲刺都以一种类型的古典波为中心。在推力1：纳米材料中的光-物质相互作用下，场势有限差分计算电磁学的最新算法进展将与那些涉及使用密度矩阵进行量子输运模拟的算法进展相结合。在这个新的自洽求解器中，量子输运和经典电动力学将在每个时间步长自洽耦合。在推力2：纳米材料中的声-物质相互作用下，无序介质中弹性波散射的最新计算进展将与使用密度矩阵进行量子电子输运模拟的计算进展相结合。新的模拟将分析表面声波驱动发光纳米结构中的量子电子传输的系统。这些代码将通过GitHub以开源的形式发布，并将使设计新设备的实验者受益。本科生研究人员也将参与这一项目。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The ability to control the movement of electrons in semiconductor devices lies at the core of electronics, photonics, and phononics, which are basic-science fields that give rise to technological advances in energy, communication, sensing, information science, and security. Electrons are very small particles found in every atom, and they obey the laws of quantum mechanics, which makes it challenging to interact with them and control their motion in a highly predictable fashion. The central question behind this project is how one can use light and sound, both classical waves commonly encountered in daily lives, to excite or drive electrons in modern semiconductors devices. The size of these devices is a few nanometers, less than a thousandth of the thickness of a strand of human hair. Owing to the device small size and inescapable imperfections, it is much more challenging to understand how light and sound interact with electrons in devices than it is to answer the same question in much larger systems, such as bulk materials. However, the small device size may also lead to the emergence of striking new phenomena with great technological impact. To that end, state-of-the-art simulation software to analyze how electrons in nanoscale devices interact with classical light and sound will be developed during this project. Microscopic theory and accurate simulation tools benchmarked against experiment, such as those that will be developed during the course of this project, are invaluable for deepening the understanding of the world at the nanoscale and for predicting new phenomena and functionalities, all at a fraction of experimental cost. This project will benefit experimental groups in industry and academia by helping design new devices. The codes will be distributed as open source through GitHub to ensure widespread use.How can classical waves, electromagnetic or acoustic, be used to excite or drive quantum electronic systems in modern nanostructures? This question cuts through electronics, photonics, and phononics, and has technological repercussions ranging from energy to communication, sensing, information science, and security. The answer requires a deep understanding of the physical processes that characterize the interplay of charge with light and sound in nanomaterials and nanostructures, and the answer differs greatly from its analogue in bulk materials because the low dimensionality and small size of these systems result in their sensitivity to boundaries and edges, disorder, surrounding materials properties, and may also lead to the emergence of striking new plasmonic, polaronic, and excitonic phenomena. To that end, the objective in this project is to develop and deploy a comprehensive modeling approach, employing state-of-the-art simulation techniques for classical electromagnetic and elastic waves coupled with an efficient density-matrix technique for quantum electronic transport in order to understand and harness the interplay of light, sound, and charge at the nanoscale. The work will be organized into two thrusts, each centered on one type of the classical wave. Under Thrust 1: Light–matter interaction in nanomaterials, recent algorithmic advances in field-potential finite-difference time-domain computational electromagnetics will be integrated with those involving quantum transport simulation using the density matrix. In this new self-consistent solver, quantum transport and classical electrodynamics will be coupled self-consistently and at every time step. Under Thrust 2: Sound-matter interaction in nanomaterials, recent computational advances in the simulation of elastic-wave scattering in disordered media will be integrated with those involving quantum electron transport simulation using the density matrix. The new simulation will analyze systems in which surface acoustic waves drive quantum electronic transport in light-emitting nanostructures. The codes will be distributed as open source through GitHub, and will benefit experimentalists designing new devices. Undergraduate researchers will also take part in this project.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.