Coherent propagation and decay of quasi-particles

准粒子的相干传播和衰变

• 批准号: 471475967
• 负责人: Professor Dr. Maurits Haverkort
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/471475967?language=en
• 关键词: Coherent; propagation; decay; quasi; particles

We will develop a real-space / momentum, real-time / frequency Green's function method to describe the decay of quasi-particles in the dynamics of realistic materials as seen in local and non-local $n$-point correlation functions. The focus will be on the decay due to charge scattering for either low energy excitations (magnons) or high energy excitations (x-ray induced excitons and resonances). Project P7 directly contributes to thread 3 on dynamical properties of correlated models and materials in excited states.We will extend the methods in our program package Quanty to calculate the dynamics of x-ray excited core states, and low energy magnetic and orbital excitations to include a material specific self-energy describing the decay. We will focus on correlated metals relevant within QUAST such as, Ce3Bi4Pd3, CeRu4Sn6, Co3Sn2S2, CeBa7Au4Si40 and TaS2 experimentally investigated within P1, P3, and P6. We will use LDA+DMFT as a starting point for the electronic structure calculations. We will implement methods to calculate the change in the dynamics of x-ray core excited states as a result of the Auger-Meitner decay due to Coulomb scattering of local electrons into the continuum. In order to evade excessively large Hilbert spaces, we will implement the Coulomb scattering into non-local states as a self-energy for the electronic propagation of the quasi-particle. The propagating quasi-particle in the case of x-ray excitations is a core-hole - valence-electron exciton. Having a non-zero self-energy makes the description of the dynamics easier as the system forgets long-time behaviour. We can test our methods by comparing 2- and 4-point correlation functions to the x-ray absorption and resonant inelastic x-ray scattering of the model correlated metals measured (P1) and calculated (P1, P5) within QUAST. After we understand how to treat the self-energy of core excited states we will implement the self-energy of low energy magnetic excitations due to charge scattering. In the frequency domain this allows one to not only obtain an energy momentum dispersion of magnetic excitations in materials like Ce3Bi4Pd3, CeRu4Sn6, Co3Sn2S2 and CeBa7Au4Si40 but also their line widths. In the time domain the self-energy sets a time scale for the transfer of excitation energy between the spin and charge degrees of freedom of the material. Thereby setting time scales for the equilibration of the slow spin dynamics (P8).

我们将开发一种实时 /频率绿色的函数方法，以描述在逼真的材料的动力学中描述准粒子的衰减，如本地和非本地$ n $ - 点相关函数所示。由于电荷散射的低能激发（镁）或高能量激发（X射线诱导的激子和共振），重点将放在衰减上。 Project P7直接有助于螺纹3在激发态下相关模型和材料的动力学特性上。我们将扩展程序包装中的方法，以计算X射线激发核心状态的动力学，而低能磁和轨道激励，以包括描述衰变的材料特定的自我能源。我们将重点关注与等式中相关的金属，例如Ce3Bi4pd3，CERU4SN6，CO3SN2S2，CEBA7AU4SI40和TAS2在P1，P3和P6中进行了实验研究。我们将使用LDA+DMFT作为电子结构计算的起点。 我们将通过螺旋芯激发态动力学的变化来实施方法，这是由于螺旋杆衰变而导致的，这是由于将局部电子散射到连续体中而导致的。为了逃避过多的希尔伯特空间，我们将将库仑散射到非本地状态，以作为准颗粒的电子传播的自能力。在X射线激发的情况下，繁殖的准粒子是核心 - 孔 - 电子激子激发子。随着系统忘记长期行为，具有非零的自我能力使对动态的描述更加容易。我们可以通过将2和4点相关函数与模型相关金属的X射线吸收和共振的非弹性X射线散射（P1）（P1）和计算（P1，P5）进行比较，并通过比较2和4点相关函数来测试我们的方法。在了解如何处理核心激发态的自我能源之后，我们将由于电荷散射而实施低能磁激励的自我能源。在频域中，这不仅允许在诸如CE3BI4PD3，CERU4SN6，CO3SN2S2和CEBA7AU4SI40之类的材料中获得磁激励的能量动量分散，还可以获得线条宽度。在时间域中，自我能源为自旋和电荷自由度之间的激发能传递的时间尺度设定了时间尺度。从而为慢自旋动力学的平衡设置时间尺度（P8）。