分子尺度上水和金属表面的相互作用

虽然水普遍存在,但人们在分子尺度上对水与固体表面的相互作用的理解却仍然处在初始阶段.文章简述了20年来人们对水在贵金属表面的吸附和浸润过程进行微观尺度上研究的进展,分析和讨论了水和表面作用的一般规律和所获得的经验教训,特别着重讨论了对上世纪80年代人们提出的经典双层冰模型的修正.     

Fermionic Analogue of High Temperature Hawking Radiation in Black Phosphorus

Time-periodic laser driving can create nonequilibrium states not accessible in equilibrium,opening new regimes in materials engineering and topological phase transitions.We report that black phosphorus(BP) exhibits spatially nonuniform topological Floquet-Dirac states under laser illumination,mimicking the "gravity" felt by fermionic quasiparticles in the same way as that for a Schwarzschild black hole(SBH).Quantum tunneling of electrons from a type-Ⅱ Dirac cone(inside BH) to a type-Ⅰ Dirac cone...     

Screening Promising CsV3Sb5-Like Kagome Materials from Systematic First-Principles Evaluation

The Cs V₃Sb₅ kagome lattice holds the promise for manifesting electron correlation,topology and superconductivity.However,by far only three Cs V₃Sb₅-like kagome materials have been experimentally spotted.We enlarge this family of materials to 1386 compounds via element species substitution,and the further screening process suggests that 28 promising candidates have superior thermodynamic stability,hence they are highly likely to be synthesizable.Moreov...     

Energy Landscape and Phase Competition of CsV3Sb5, CsV6Sb6 and TbMn6Sn6-Type Kagome Materials

Finding viable Kagome lattices is vital for materializing novel phenomena in quantum materials.In this study,we performed element substitutions on CsV₃Sb₅ with space group P 6/mmm,TbMn₆Sn₆ with space group P 6/mmm,and CsV₆Sb₆ with space group ■,as the parent compounds.Totally 4158 materials were obtained through element substitutions,and these materials were then calculated via density functional theory in high-throughput mode.Aft...     

水在金属表面的氢键网络结构振动谱研究

用从头计算分子动力学模拟方法研究了水在Pt(111)表面上的吸附。总能优化和振动谱分析都表明，在这个表面上水以有序的分子态双层结构存在。这一结论和最近对水在Ru(0001)表面上吸附的计算结果相悖，但和已有的实验相符。此外，文章作者首次确定双层结构中存在两种不同的氢键形式。这两种氢键可以通过0H伸缩振动模的振动谱得到直接证实。     

电子的谷自由度

电子在晶格周期性势场影响下的运动遵循布洛赫定理. 布洛赫电子除了具有电荷和自旋两个内禀自由度外, 还有其他内禀自由度. 能带色散曲线上的某些极值点作为谷自由度, 具有独特的电子结构和运动规律. 本文从布洛赫电子的谷自由度出发, 简单介绍传统半导体的谷电子性质研究现状, 并重点介绍新型二维材料体系, 如石墨烯、硅烯、硫族化合物等材料中谷相关的物理特性. 有效利用谷自由度的新奇输运特性, 将其作为信息的载体可以制作出新颖的纳米光电子器件, 并有望造就下一代纳电子器件的新领域, 即谷电子学(valleytronics).     

Engineering Interlayer Hybridization in Energy Space via Dipolar Overlayers

The interlayer hybridization(IH) of van der Waals(vdW) materials is thought to be mostly associated with the unignorable interlayer overlaps of wavefunctions(t) in real space. Here, we develop a more fundamental understanding of IH by introducing a new physical quantity, the IH admixture ratio α. Consequently, an exotic strategy of IH engineering in energy space can be proposed, i.e., instead of changing t as commonly used, α can be effectively tuned in energy space by changing the on-site energ...     

纳米尺度上的表面电子动力学

揭示物质结构、物质间相互作用及其运动规律是物理学永恒的主题。经过百多年来的努力,人们已明确了常见物质的基本结构：普通物质是由分子、离子、原子等组成。而作为基本单元的原子又是由电子和原子核两部分结合而成;欲了解物质结构和运动规律就不得不深入地认识原子核周围的电子分布和电子运动形式。原子的运动在相当程度上也是由它们的电子结构和运动规律所决定和驱动的。所以,电子动力学的研究对于理解基本物质组成和动力学规律、探索新奇的物理现象、发展新材料有着举足轻重的影响。     

c轴取向SiC衬底MgB_2超导厚膜的制备及性质

通过混合物理化学气相沉积法(Hybrid Physical-chemical Vapor Deposition,简称HPCVD),我们在SiC衬底上制备出了c取向8μm厚的MgB2超导厚膜.电性质测量表明其起始超导转变温度是41.4K,转变宽度为0.5K,剩余电阻比率RRR～7.磁性质测量表明5K和零场下样品的临界电流密度达到了1.7×106A/cm2.