Transition of recollision trajectories from linear to elliptical polarization.

Using a classical ensemble method, we revisit the topic of recollision and nonsequential double ionization with elliptically polarized laser fields. We focus on how the recollision mechanism transitions from short trajectories with linear polarization to long trajectories with elliptical polarization. We propose how this transition can be observed by meansuring the carrier-envelop-phase dependence of the correlated electron momentum spectra using currently available few-cycle laser pulses.

An atomically thin layer of Ru/MoS2 heterostructure: structural, electronic, and magnetic properties.

The fabrication of a transition metal (TM) atomically thin layer with robust ferromagnetic ordering (FM) for the continuous miniaturization of spintronic and quantum computing devices is desired. Through first-principles calculations, we establish that Ru atoms can be epitaxially aligned on MoS2 monolayers, thus forming an atomically thin layer of 2D Ru/MoS2 heterostructure with high structural stability. The Ru layer possesses a robust FM (more than 300 K) and an out-of-plane easy axis with the magnetic anisotropy energy (MAE) of ∼3.4 meV per atom. In particular, we find that the FM can be switched by an external electric field (Efield) of 1.5 V nm-1. We propose that this atomically thin layer of Ru/MoS2 heterostructure can be used as an alternative candidate for free-standing magnetic TM layers and provides new possibilities to design 2D spintronic devices.

Highly Promoted Carrier Mobility and Intrinsic Stability by Rolling Up Monolayer Black Phosphorus into Nanoscrolls.

Rolling up two-dimensional (2D) materials into nanoscrolls could not only retain the excellent properties of their 2D hosts but also display intriguing physical and chemical properties that arise from their 1D tubular structures. Here, we report a new class of black phosphorus nanoscrolls (bPNSs), which are stable at room-temperature and energetically more favorable than 2D bP. Most strikingly, these bPNSs hold tunable direct band gaps and extremely high mobilities (e.g., the mobility of the double-layer bPNS is about 20-fold higher than that of 2D bP monolayer). Their unique self-encapsulation structure and layer-dependent conduction band minimum can largely prevent the entrance of O2 and the production of O2- and thereby suppress the possible environmental degradation as well. The enhanced intrinsic stability and promoted electronic properties render bPNSs great promise in many advanced electronics or optoelectronics applications.

Structure and magnetic properties of icosahedral PdxAg13-x (x = 0-13) clusters.

In this article, we present a modified Velocity-Verlet algorithm that makes cluster system converge rapidly and accurately. By combining it with molecular dynamics simulations, we develop an effective global sampling method for extracting isomers of bimetallic clusters. Using this method, we obtain the isomers of icosahedral PdxAg13-x (x = 0-13). Additionally, using the first-principle spin-polarized density functional theory approach, we find that each isomer still retains its icosahedral structure because of strong s-d orbital hybridization, and the cluster is more stable when a Pd atom is at the center of the cluster. With increasing x value, the magnetic moment decreases linearly from 5.0 µB at x = 0, until reaching zero at x = 5, and then increases linearly up to 8.0 µB at x = 13. By calculating the atom-projected density of states (PDOS), we reveal that the magnetic moment of PdxAg13-x mainly originates from s electrons of Ag when 0 ≤ x < 5, and d electrons of Pd when 5 < x ≤ 13. The PDOS results also show that the PdxAg13-x tends to transform from a semiconductor state to semi-metallic state when x gradually increases from 0 to 13.