Quantum anomalous Hall effect

Hall efect is a well-known electromagnetic phenomenon that has been widely applied in the semiconductor industry.he quantum Hall efect discovered in two-dimensional electronic systems under a strong magnetic ield provided new insights into condensed mater physics,especially the topological aspect of electronic states.he quantum anomalous Hall efect is a special kind of the quantum Hall efect that occurs without a magnetic ield.It has long been sought ater because its realization will signiicantly facilitate the studies and applications of the quantum Hall physics.In this paper,we review how the idea of the quantum anomalous Hall efect was developed and how the efect was inally experimentally realized in thin ilms of a magnetically doped topological insulator.     

Edge superconductivity in multilayer WTe2 Josephson junction

WTe₂, as a type-II Weyl semimetal, has 2D Fermi arcs on the (001) surface in the bulk and 1D helical edge states in its monolayer. These features have recently attracted wide attention in condensed matter physics. However, in the intermediate regime between the bulk and monolayer, the edge states have not been resolved owing to its closed band gap which makes the bulk states dominant. Here, we report the signatures of the edge superconductivity by superconducting quantum interference measurements in multilayer WTe₂ Josephson junctions and we directly map the localized supercurrent. In thick WTe₂ (, the supercurrent is uniformly distributed by bulk states with symmetric Josephson effect (). In thin WTe₂ (10 nm), however, the supercurrent becomes confined to the edge and its width reaches up to and exhibits non-symmetric behavior . The ability to tune the edge domination by changing thickness and the edge superconductivity establishes WTe₂ as a promising topological system with exotic quantum phases and a rich physics.     

单壁纳米碳管的制备及其储氢特性

单壁纳米碳管是近年来材料科学以及凝聚态物理研究的前沿和热点。本研究提出一种有效制备单壁纳米碳管的半连续氢电弧法 ,实现了高纯度单壁纳米碳管的大量制备。在室温及中等压力下测定了氢电弧法制备单壁纳米碳管的储氢容量。初步研究结果表明 :单壁纳米碳管是一种很有前途的储氢材料     

Research progresses shed light on superconductivity mechanism

The spring of 2008 saw substantial breakthroughs in superconductivity research. Four groups of physicists, one after another, achievedremarkable progresses in the study of iron-based materials after the breakthrough made by H. Hosono＇s group in Japan, providing renewed insights into the fundamental mechanism of high-temperature superconductivity （HTSC）, a perplexing enigma on the frontier of condensed matter physics.     

Non-crystalline materials

Non-crystalline materials have recently made an impact on solid state physics that threatens to relegate the role of the single crystal from its venerable position in this field to that of a particular, and not very common, example of condensed matter. The discovery that glasses need not necessarily be insulators, but can be semiconductors and even metals, has opened up a whole new field of fundamental investigation, in addition to promising a host of possible uses. In this article, some of the properties of non-crystalline materials will be described, with emphasis on current and potential applications.     

Two-dimensional matter

The study of two-dimensional matter would seem to be a completely theoretical branch of physics, were it not that such matter actually exists. There are two-dimensional gases, liquids, and crystalline solids; the analogues of conventional bulk phases, two-dimensional lattice gases, realizations of important statistical models; two-dimensional magnets, solutions, and even amorphous glasses. Indeed, much of the variety of states of bulk substances has been created in two-dimensional matter and is intensively studied in many laboratories throughout the world.     

Topological phases of quantized light

Topological photonics is an emerging research area that focuses on the topological states of classical light. Here we reveal the topological phases that are intrinsic to the quantum nature of light, i.e. solely related to the quantized Fock states and the inhomogeneous coupling strengths between them. The Hamiltonian of two cavities coupled with a two-level atom is an intrinsic one-dimensional Su-Schriefer-Heeger model of Fock states. By adding another cavity, the Fock-state lattice is extended to two dimensions with a honeycomb structure, where the strain due to the inhomogeneous coupling strengths of the annihilation operator induces a Lifshitz topological phase transition between a semimetal and three band insulators within the lattice. In the semimetallic phase, the strain is equivalent to a pseudomagnetic field, which results in the quantization of the Landau levels and the valley Hall effect. We further construct an inhomogeneous Fock-state Haldane model where the topological phases can be characterized by the topological markers. With d cavities being coupled to the atom, the lattice is extended to d − 1 dimensions without an upper limit. In this study we demonstrate a fundamental distinction between the topological phases in quantum and classical optics and provide a novel platform for studying topological physics in dimensions higher than three.     

冷原子物理

20年前,人们通过物理实验方法获得了冷原子,今天超冷原子成为了多学科交叉的物理实验室,超低温物理、超低密度凝聚态物理、超低能碰撞物理、非线性与量子原子光学、量子信息处理、精密谱与量子频率标准等研究汇聚于此。文章介绍了相关研究进展、分析了院内外发展趋势并提出了发展建议。     

新时期材料物理专业教学体系改革探析

随着我国现代化社会的不断发展,我国的教育也发展得有声有色,在新时期下,我国的高等教育呈现了全面开花的态势。材料物理是物理学的一个分支,是物理学的重要组成部分。材料物理学主要是对一些电子材料、物理元件或者是微电子元件进行研究的专业,如今我国的材料物理专业整体还存在着一定的劣势。本文对新时期材料物理专业教学体系的现状以及改革措施进行了分析与探究。     

红外光电子学研究

红外光电子学是在红外光电技术推动下不断发展的学科,其发展与半导体物理学、凝聚态物理学、微电子学以及光学等的关系越来越密切。中国科学院长期将红外光电子学作为重要发展领域予以支持,在任务带学科的模式下取得了一系列重要成果。文中还对该学科的进一步发展提出了一些想法。     

分子材料与器件

分子材料和器件主要探讨共轭有机、高分子的设计、合成,研究其聚集态结构、分子之间相互作用,光电磁物理性质及相关现象,制备器件并研究其性能,是多学科交叉前沿研究领域。该领域发展迅速,取得了许多重要突破,但仍然蕴藏着重要创新机遇。经过几代人的努力,我国在该领域已有很好的研究基础,已经占有一席之地。     

All-aqueous multiphase microfluidics

Immiscible aqueous phases, formed by dissolving incompatible solutes in water, have been used in green chemical synthesis, molecular extraction and mimicking of cellular cytoplasm. Recently, a microfluidic approach has been introduced to generate all-aqueous emulsions and jets based on these immiscible aqueous phases; due to their biocompatibility, these all-aqueous structures have shown great promises as templates for fabricating biomaterials. The physico-chemical nature of interfaces between two immiscible aqueous phases leads to unique interfacial properties, such as an ultra-low interfacial tension. Strategies to manipulate components and direct their assembly at these interfaces needs to be explored. In this paper, we review progress on the topic over the past few years, with a focus on the fabrication and stabilization of all-aqueous structures in a multiphase microfluidic platform. We also discuss future efforts needed from the perspectives of fluidic physics, materials engineering, and biology for fulfilling potential applications ranging from materials fabrication to biomedical engineering.     

Critical couplings in topological-insulator waveguide-resonator systems observed in elastic waves

Waveguides and resonators are core components in the large-scale integration of electronics, photonics and phononics, both in existing and future scenarios. In certain situations, there is critical coupling of the two components; i.e. no energy passes through the waveguide after the incoming wave couples into the resonator. The transmission spectral characteristics resulting from this phenomenon are highly advantageous for signal filtering, switching, multiplexing and sensing. In the present study, adopting an elastic-wave platform, we introduce topological insulator (TI), a remarkable achievement in condensed matter physics over the past decade, into a classical waveguide-ring-resonator configuration. Along with basic similarities with classical systems, a TI system has important differences and advantages, mostly owing to the spin-momentum locked transmission states at the TI boundaries. As an example, a two-port TI waveguide resonator can fundamentally eliminate upstream reflections while completely retaining useful transmission spectral characteristics, and maximize the energy in the resonator, with possible applications being novel signal processing, gyro/sensing, lasering, energy harvesting and intense wave–matter interactions, using phonons, photons or even electrons. The present work further enhances confidence in using topological protection for practical device performance and functionalities, especially considering the crucial advantage of introducing (pseudo)spins to existing conventional configurations. More in-depth research on advancing phononics/photonics, especially on-chip, is foreseen.     

结合学科特色构建材料物理专业课程体系的探索

以工科院校材料物理专业人才培养目标为出发点,结合学科特色,从材料物理专业的核心课程、专业基础课程、专业方向课程、实验及实践环节几方面探讨了材料物理专业课程体系的改革。     

2维原子晶体材料的研究现状与未来

近年来,以石墨烯为代表的2维原子晶体材料因其独特的2维结构、丰富而新奇的物理化学性质与广阔的应用前景,迅速成为凝聚态物理与材料科学领域的研究前沿。本文概要地介绍了石墨烯的制备、石墨烯的物理与物性、石墨烯的可能应用及其他2维原子晶体材料的研究进展,并对2维原子晶体材料的未来发展趋势进行了分析与讨论。     

4D spinless topological insulator in a periodic electric circuit

According to the mathematical classification of topological band structures, there exist a number of fascinating topological states in dimensions larger than three with exotic boundary phenomena and interesting topological responses. While these topological states are not accessible in condensed matter systems, recent works have shown that synthetic systems, such as photonic crystals or electric circuits, can realize higher-dimensional band structures. Here, we argue that, because of its symmetry properties, the 4D spinless topological insulator is particularly well suited for implementation in these synthetic systems. We explicitly construct a 2D electric circuit lattice, whose resonance frequency spectrum simulates the 4D spinless topological insulator. We perform detailed numerical calculations of the circuit lattice and show that the resonance frequency spectrum exhibits pairs of 3D Weyl boundary states, a hallmark of the nontrivial topology. These pairs of 3D Weyl states with the same chirality are protected by classical time-reversal symmetry that squares to +1, which is inherent in the proposed circuit lattice. We also discuss how the simulated 4D topological band structure can be observed in experiments.     

技工学校物理教学中对学生兴趣的培养

很长时间以来,在我们传统的教学过程中,教师仅仅看重的是学生是否学会,往往忽略了学生自主思考问题的过程。随着时代的发展,竞争在当今这个社会中显得越来越激烈,对于我们所培养出来的人才,他们自主思考问题,解决问题的能力越来越重要。在技工学校中,物理教材一般都是在实验的基础上进行的,以便让学生通过直观的实验更好地接收知识。那么教师应该如何在有限的课堂上,提高学生学习物理的兴趣,从而达到事半功倍的效果呢？     

A major milestone in nanoscale material science: the 2002 Benjamin Franklin Medal in Physics presented to Sumio Iijima

The Franklin Institute, Philadelphia, Pennsylvania, awarded the 2002 Benjamin Franklin Medal in physics to Sumio Iijima for his discovery and elucidation of the atomic structure and helical character of multi- and single-wall carbon nanotubes. His pioneering work created a new, tremendously active and expanding area in the field of nanoscience and technology that involves condensed matter and material scientists, chemists and computer scientists. Iijima has also made key contributions to the mechanisms that are involved in the growth of carbon nanotubes, to the role of pentagonal and heptagonal carbon rings in the formation of caps that form at the ends of the nanotubes and to the encapsulation of molecules within the nanotubes.     

Conversation with Chen-Ning Yang: reminiscence and reflection

Chen-Ning Yang ( ) is the most distinguished Chinese theoretical physicist. In 1954, together with Robert Mills, he formulated the Yang–Mills Gauge Theory, which led to the development of the Standard Model, the leading framework for understanding particle physics. In 1956, Yang and Tsung-Dao Lee ( ) proposed the possibility of parity non-conservation in weak interaction, which won them the Nobel Prize in Physics in 1957. Besides these two major achievements, Yang made many other seminal contributions to particle physics, statistical physics and condensed matter physics. At the end of 2003, Yang returned to China from the US and established the Institute for Advanced Study at Tsinghua University in Beijing. NSR’s Executive Editor-in-Chief Mu-ming Poo ( ), a neurobiologist, and Alexander Wu Chao ( ), an accelerator physicist at Stanford University, talked with Professor Yang on a variety of topics, ranging from his retrospective view on Yang–Mills theory, on his contemporary physicists, on tastes in scientific research, and on the current and future developments of Chinese science. The following is an excerpt from this conversation that took place on 21 March 2019 at Tsinghua University, Beijing.