We report measurements of the spin torque efficiencies in perpendicularly magnetized Pt/Co bilayers where the Pt resistivity ρPt is strongly dependent on thickness tPt. The dampinglike spin Hall torque efficiency per unit current density ξDLj varies significantly with tPt, exhibiting a peak value ξDLj=0.12 at tPt=2.8-3.9 nm. In contrast, ξDLj/ρPt increases monotonically with tPt and saturates for tPt>5 nm, consistent with an intrinsic spin Hall effect mechanism, in which ξDLj is enhanced by an increase in ρPt.

Motivated by experiments in Munich [M. Schreiber et al., Science 349, 842 (2015).SCIEAS0036-807510.1126/science.aaa7432], we study the dynamics of interacting fermions initially prepared in charge density wave states in one-dimensional bichromatic optical lattices.

Heterostructures utilizing topological insulators exhibit a remarkable spin-torque efficiency. However, the exact origin of the strong torque, in particular whether it stems from the spin-momentum locking of the topological surface states or rather from spin-Hall physics of the topological-insulator bulk, remains unclear. Here, we explore a mechanism of spin-torque generation purely based on the topological surface states. We consider topological-insulator-based bilayers involving ferromagnetic metal (TI/FM) and magnetically doped topological insulators (TI/mdTI), respectively.

Why do animals move the way they do? Bacteria, insects, birds, and fish share with us the necessity to move so as to live. Although each organism follows its own evolutionary course, it also obeys a set of common laws. At the very least, the movement of animals, like that of planets, is governed by Newton's law: All things fall. On Earth, most things fall in air or water, and their motions are thus subject to the laws of hydrodynamics. Through trial and error, animals have found ways to interact with fluid so they can float, drift, swim, sail, glide, soar, and fly.

Highly parallel graphics processing units (GPUs) can improve the speed of micromagnetic simulations significantly as compared to conventional computing using central processing units (CPUs). We present a strategy for performing GPU-accelerated micromagnetic simulations by utilizing cost-effective GPU access offered by cloud computing services with an open-source Python-based program for running the MuMax3 micromagnetics code remotely. We analyze the scaling and cost benefits of using cloud computing for micromagnetics. © 2015 Elsevier B.V.

Using an exact numerical solution and semiclassical analysis, we investigate quantum oscillations (QOs) in a model of a bilayer system with an anisotropic (elliptical) electron pocket in each plane. Key features of QO experiments in the high temperature superconducting cuprate YBCO can be reproduced by such a model, in particular the pattern of oscillation frequencies (which reflect "magnetic breakdown" between the two pockets) and the polar and azimuthal angular dependence of the oscillation amplitudes.

We propose an experimental protocol to directly observe the Kondo effect by scattering ultracold atoms. We propose using an optical Feshbach resonance to engineer Kondo-type spin-dependent interactions in a system with ultracold Li6 and Rb87 gases. We calculate the momentum transferred from the Rb87 gas to the Li6 gas in a scattering experiment and show that it has a logarithmically enhanced temperature dependence, characteristic of the Kondo effect, and analogous to the resistivity of alloys with magnetic impurities.

The electrical and thermal Hall conductivities of the cuprate superconductor YBa2Cu3Oy, σxy and κxy, were measured in a magnetic field up to 35 T, at a hole concentration (doping) p=0.11. In the T=0 limit, we find that the Wiedemann-Franz law, κxy/T=(π2/3)(kB/e)2σxy, is satisfied for fields immediately above the vortex-melting field Hvs. This rules out the existence of a vortex liquid at T=0 and it puts a clear constraint on the nature of the normal state in underdoped cuprates, in a region of the doping phase diagram where charge-density-wave order is known to exist.

Structuring ionic solids at the nanoscale with block copolymers (BCPs) is notoriously difficult due to solvent incompatibilities and strong driving forces for crystallization of the inorganic material.

Research on high-temperature superconducting cuprates is at present focused on identifying the relationship between the classic 'pseudogap'phenomenon and the more recently investigated density wave state. This state is generally characterized by a wavevector Q parallel to the planar Cu-O-Cu bonds along with a predominantly d-symmetry form factor (dFF-DW).