BITT - Bremen Initiative on Time-dependent Transport: Atomistic approaches towards photo-induced quantum transport dynamics across single molecules

我们的目标是应用和验证现有的国家的最先进的密度泛函为基础的方法（平面波，本地轨道和最小基础DFTB）在握手与量子化学方法进行计算的断裂结内的分子和不同的金属（Au，Cu）和半导体（Si）基板，以分类准确和实验相关的结合几何形状。中心目标是确定最低能量的配置，并提高对不同分子如何在真空和环境条件下反应和结合到各种底物的理解。将进行分子动力学模拟，以研究吸附物的热波动和动力学性质。这在断开结和扫描探针实验的背景下是特别重要的，这些实验在大多数情况下显示出明显的动态特征，这是由于在噪声信号中也可以看到的传导路径的重复形成。在获得详细的原子几何形状后，我们将应用从头计算和DFTB代码来表征电子结构。精确的量子化学计算和相关修正将应用于小系统，以测试和验证有效的单粒子方法。（STM图像和STS光谱）将在非平衡绿色的框架内进行。s函数方法，以确定不同表面/吸附物的表面重建和形态，并与实验进行比较。我们还将继续开发/改进了我们的非平衡绿色函数- DFTB技术，包括对电子-电子相关性的多体校正，并将其应用于单分子特征电子输运信号的定量计算。这包括I-V特性，IETS数据，噪声分析和功耗。在与实验研究的密切合作中，我们的目标是了解分子接触键合配置，在施加偏压和耦合到环境（接触，耗散，解决方案）下的分子的动态构象行为，我们的目标是预测，这将如何反映在传输数据和分子器件的功能行为。

We aim to apply and validate existing State-of-the-Art density-functional-based approaches (Plane Wave, Local Orbital and minimal basis DFTB) in handshaking with quantum chemistry methods to perform calculations of molecules within break-junctions and on different metallic (Au, Cu) and semiconducting (Si) substrates in order to classify accurate and experimental relevant binding geometries. The central goal is to identify the lowest energy configurations and to improve the understanding on how different molecules react and bind to various substrates in vacuo and under environmental conditions. Molecular Dynamics simulations will be performed in order to study thermal fluctuations and dynamical properties of the adsorbates. This is particularly important in the context of break-junction and scanning probe experiments which in most cases show pronounced dynamical signatures due to repeated formation of conduction paths that can also be seen in noise signal. Having obtained the detailed atomic geometries, we will apply ab-initio calculations together with the DFTB code for characterising the electronic structure. Accurate quantum chemistry calculations with correlation-corrections will be applied to small systems to test and validate the effective single-particle approaches.Simulations of scanning tunnelling data (STM images and STS-spectra) will be performed within the framework of non-equilibrium Green¿s functions methods, in order to identify surface reconstructions and morphologies of different surfaces/adsorbates in comparison with experiments.We further will continue developing/improving our non-equilibrium Green¿s functions- DFTB techniques including many-body corrections to the electron-electron correlations and apply this for quantitative calculations of characteristic electronic transport signals across single molecules. This include I-V characteristics, IETS-data, noise analysis and power dissipation. In close collaboration with experimental investigations we aim to understand the molecule contact bonding configurations, the dynamical conformational behaviour of the molecules under applied bias and in coupling to the environment (contacts, dissipation, solution) and we aim to predict, how this will be reflected in the transport data and the functional behaviour of the molecular device.