Non-perturbative dynamics of flat-band systems with correlated disorder

We develop a numerical method for the time evolution of Gaussian wave packets on flat-band lattices in the presence of correlated disorder.To achieve this,we introduce a method to generate random on-site energies with prescribed correlations.We verify this method with a one-dimensional(1D)cross-stitch model,and find good agreement with analytical results obtained from the disorder-dressed evolution equations.This allows us to reproduce previous findings,that disorder can mobilize 1D flat-band states which would otherwise remain localized.As explained by the corresponding disorder-dressed evolution equations,such mobilization requires an asymmetric disorder-induced coupling to dispersive bands,a condition that is generically not fulfilled when the flat-band is resonant with the dispersive bands at a Dirac point-like crossing.We exemplify this with the 1D Lieb lattice.While analytical expressions are not available for the two-dimensional(2D)system due to its complexity,we extend the numerical method to the 2D a–T3 model,and find that the initial flat-band wave packet preserves its localization when a=0,regardless of disorder and intersections.However,when a̸=0,the wave packet shifts in real space.We interpret this as a Berry phase controlled,disorder-induced wave-packet mobilization.In addition,we present density functional theory calculations of candidate materials,specifically Hg1−xCdxTe.The flat-band emerges near the G point(α=0)in the Brillouin zone.

Electrically controllable spin filtering in zigzag phosphorene nanoribbon based normal–antiferromagnet–normal junctions

We investigated the electric controllable spin-filtering effect in a zigzag phosphorene nanoribbon(ZPNR) based normal–antiferromagnet–normal junction. Two ferromagnets are closely coupled to the edges of the nanoribbon and form the edge-to-edge antiferromagnetism. Under an in-plane electric field, the two degenerate edge bands of the edge-to-edge antiferromagnet split into four spin-polarized sub-bands and a 100% spin-polarized current can be easily induced with the maximal conductance 2e~2/h. The spin polarization changes with the strength of the electric field and the exchange field,and changes sign at opposite electric fields. The spin-polarized current switches from one edge to the other by reversing the direction of the electric field. The edge current can also be controlled spatially by changing the electric potential of the scattering region. The manipulation of edge current is useful in spin-transfer-torque magnetic random-access memory and provides a practical way to develop controllable spintronic devices.

零售银行业务关心的焦点问题及启示

一、国际零售银行业界关心的焦点问题 (一)业务外包(outsourcing)是大多数银行提高核心竞争力的重要方式.

网点转型的难点及对策

网点转型重塑网点价值 网点转型是指网点的业务功能由核算交易主导型向营销服务主导型的转变。具体来说，就是用统一的标准，规范网点的服务营销模式，实现服务标准化和客户体验的一致性，以提高产品销售能力，提升客户满意度。国内银行业提出这个概念是在2002年左右。目前各家银行都在积极推进网点功能的转变，虽然每家银行的方法和侧重点不太一样，但其目的是一样的，就是提高网点的营销和服务能力。

Novel 0–π transitions in Josephson junctions between noncentrosymmetric superconductors

We study the Josephson effect between two noncentrosymmetric superconductors（NCSs） with opposite polarization vectors of Rashba spin–orbit coupling（RSOC）.We find a 0–π transition driven by the triplet–singlet ratio of NCSs.Different from conventional 0–π transitions,the Andreev bound states change their energy range instead of phase shift in the 0–π transition found here.This novel property results in a feature that the critical current becomes almost zero at the transition point,not only a minimum.Furthermore,when the directions of RSOC polarization vectors are the same in two NCSs,the similar effect can also be found in the presence of a perpendicular exchange field or a Dresselhause spin–orbit coupling in the interlayer.We find novel oscillations of critical current without 0–π transition.These novel 0–π transitions or oscillations of critical current present new understanding of the Josephson effect and can also serve as a tool to determine the unknown triplet–singlet ratio of NCSs.

类石墨烯材料中应力调制的量子泵浦效应

通过对应力及电势垒的周期调制,在石墨烯及类石墨烯蜂窝格子材料中泵浦出能谷流.应力在能谷K和K'处诱导的符号相反的矢势,等效于加载K和K'能谷处的应力泵浦信号间有一个π相位差,导致纯能谷流的产生.当在含有自旋轨道耦合的类石墨烯蜂窝格子材料中存在一个交错子格子势时,经由自旋-能谷锁定相,泵浦出的纯能谷流可伴随着纯的自旋流.再引入一个交换场后,可通过泵浦得到电荷流、能谷极化流以及自旋极化流.

The magneto-thermoelectric effect of graphene with intra-valley scattering

We present a qualitative and quantitative study of the magneto-thermoelectric effect of graphene. In the limit of impurity scattering length being much longer than the lattice constant, the intra-valley scattering dominates the charge and thermal transport. The self-energy and the Green＇s functions are calculated in the self-consistent Born approximation. It is found that the longitudinal thermal conductivity splits into double peaks at high Landau levels and exhibits oscillations which are out of phase with the electric conductivity. The chemical potential-dependent electrical resistivity, the thermal conductivities, the Seebeck coefficient, and the Nernst coefficient are obtained. The results are in good agreement with the experimental observations.

Topological phase in one-dimensional Rashba wire

We study the possible topological phase in a one-dimensional（1D） quantum wire with an oscillating Rashba spin–orbital coupling in real space. It is shown that there are a pair of particle–hole symmetric gaps forming in the bulk energy band and fractional boundary states residing in the gap when the system has an inversion symmetry. These states are topologically nontrivial and can be characterized by a quantized Berry phase ±π or nonzero Chern number through dimensional extension. When the Rashba spin–orbital coupling varies slowly with time, the system can pump out 2 charges in a pumping cycle because of the spin flip effect. This quantized pumping is protected by topology and is robust against moderate disorders as long as the disorder strength does not exceed the opened energy gap.

银行系寿险公司转型的难点与对策

经过几年的快速发展,银行系寿险公司以其鲜明的特点成为中国寿险行业的生力军。银行系寿险公司的业务模式和发展方式也决定了在其转型过程中,回归保险保障的重要意义。当前,银行系寿险公司转型面临着战略定位、资本补充、模式创新、文化塑造等诸多问题,转型成功的关键是要坚持供给侧结构性改革,坚持高质量发展,以客户为中心,确立特定细分市场的竞争优势,成为母行金融生态系统中的重要环节,专注于风险保障和价值创造,培养市场化竞争能力。同时,要尽快形成市场化、多元化的资本补充机制,塑造先进的保险文化。