报告介绍 报告摘要：　　拓扑电子物态是当前凝聚态及材料物理领域的重要关注焦点。声子晶体是具有宏观周期性结构的人工材料，其中的声子态或声波态也可具有异于寻常的拓扑性质。本报告主要介绍介绍两类拓扑声子晶体，即能谷声子晶体和外尓声子晶体，内容涉及能谷声子晶体中的能谷态的涡旋特性、拓扑相及拓扑相变、能谷边缘态及拓扑输运，以及外尓声子晶体中的Weyl点、费米弧表面态及其拓扑输运等。报告人简介：　　刘正猷，国家杰出青年基金获得...

报告介绍 Abstract：　　Perovskites include a family of functional materials with ABX3 structure. Barium titanite (BaTiO3) is a typical inorganic ferroelectric perovskite that possesses switchable spontaneous polarization. Ferroelectric polarizations are usually switched by electric field, but other forms of switching mechanisms have been demonstrated, such as flexoelectricity, pyroelectric effect, and change...

报告介绍 Abstract：　　Although the richness of spatial symmetries has led to a rapidly expanding inventory of possible topological crystalline (TC) phases of electrons, physical realizations have been slow to materialize due to the practical difficulty to ascertaining band topology in realistic calculations. Here, we integrate the recently established theory of symmetry indicators of band topology into firs...

报告介绍 Abstract:　　Structures and processes at surfaces and interfaces are often crucial for the performance of functional materials. Understanding these processes on an atomic level is not only scientifically challenging and interesting, but also technologically relevant. In this talk I will illustrate how quantum chemistry calculations can elucidate processes relevant in (electro-) chemical energy stora...

报告介绍 Abstract：　　Nature uses oxidative couplings to construct carbon-carbon, carbon-oxygen, and carbon-nitrogen bonds with a high degree of efficiency. Surprisingly, few laboratory equivalents are as selective or as efficient as the biological versions. The use of parallel microscale screening to discover selective and efficient catalysts for such processes using oxygen as the terminal oxidant will be ...

报告介绍 Abstract:　　Bypassing the diffraction limit of conventional limit of light, near-field microscopy has emerged as an invaluable tool for nanometer-resolved optical investigations of functional materials. This technique has been conventionally restricted to ambient conditions, impeding the low temperature investigation of quantum materials using nano-optics. Here I present several key discoveries fro...

报告介绍 Abstract:　　Over the past decade, optical near-field techniques, especially the scattering-type scanning near-field optical microscope (s-SNOM), have undergone tremendous development. This is partly due to the ever-increasing demand for the exploration of the nano-world and partly due to the many technical advances in laser and scanning probe technologies. I will use this opportunity to report the ...

报告介绍 Abstract:　　We have found that the strong spin Hall effect in TaAs is mainly dominated from the Weyl points and nodal-line-like Fermi surface, which implies a strong interplay between the topological band structure and Berry curvature in topological semimetals. With this guiding principle, we have successfully understood the strong spin Hall effect in IrO2 and found the nodal line band structures i...

报告介绍 Abstract：　　Real-time time-dependent density functional theory (RT-TDDFT) is known to be hindered by the very small time step (attosecond or smaller) needed in the numerical simulation due to the fast oscillation of electron wavefunctions, which significantly limits its range of applicability for the study of ultrafast dynamics. In this talk, we will demonstrate that such oscillation can be consid...

报告介绍 报告摘要：　　When singleatom meets 2D materials, many exotic physical and chemical properties emerge inthis hybrid system, which makes it highly desirable for a wide range ofapplications. In the first part of my talk, I will describe our recent scanningtunneling microscopy (STM) and atomic force microscopy (AFM) studies of singlemolecules/atoms on 2D materials with an aim to understand how the ener...

报告介绍 Abstract：　　In this talk, I will presentour recent experimental observations of the large-scale mesoscopic transport innanostructured graphene, and tunnelling spectroscopy in gate-inducedsuperconductivity in MoS2.　　I will first talkabout the observation of Anderson localization in two dimensions through samplesize scaling on nanostructured graphene. The localization length is observed toincrease...

报告介绍 Abstract:　　A focus of my research is to thedevelop simulation methods that reveal the mechanistic details of quantummechanical reactions that are central to biological, molecular, andheterogenous catalysis. The nature of this effort is three-fold: we work from thefoundation of quantum statistical mechanics and semiclassical dynamics todevelop methods that significantly expand the scope and reliabi...

报告介绍 Abstract：  　　Transition metal oxides exhibit a wide range of exotic phenomena from metal-insulator transition, colossal magnetoresistance to high-temperature superconductivity. In this talk, we focus on one important class of transition metal oxides, namely double perovskite oxides. We show that: i) a magnetic transition (from paramagnetic to long-range magnetically ordered) can simultaneous...

报告介绍 Abstract： 　　The Paul Scherrer Institute (PSI) runs Switzerland's Large-Scale research facilities for users from the domestic and international scientific community, and is one of only two locations in the world providing the three complementary probes of synchrotron and free electron laser X-rays, neutrons and muons at one site. The Swiss Light Source (SLS) at PSI provides photon beams of hi...

报告介绍 报告摘要：　　随着芯片集成度不断提高，半导体器件尺寸逐渐接近物理极限，传统半导体信息技术面临困难。另一方面，关联电子材料中自旋、轨道、电荷和晶格自由度之间的强烈耦合导致复杂的相图和丰富而敏感的宏观物性变化，为新型器件应用提供了可能。利用氧化物关联电子系统中的新奇量子效应来发展新一代氧化物电子学存储和处理器件成为研究的热点。报告首先简单介绍激光脉冲沉积制备外延异质结构的原理，然后讨论若干极性/非极性界...

报告介绍 报告摘要：　　Few-layer black phosphorus is a newly emerged two-dimensional material. It has many interesting properties such as strong anisotropy and significant layer-dependence of the electronic structures. The bandgap of few-layer black phosphorus is in the infrared frequency range, bridging the gap of other 2D materials: zero bandgap graphene and visible frequency bandgap transition metal dicha...