Tilley Childers (zipperpansy11)

Surface magnetism and its correlation with the electronic structure are critical to understanding the topological surface state in the intrinsic magnetic topological insulator MnBi_2Te_4. Here, using static and time resolved angle-resolved photoemission spectroscopy (ARPES), we find a significant ARPES intensity change together with a gap opening on a Rashba-like conduction band. Comparison with a model simulation strongly indicates that the surface magnetism on cleaved MnBi_2Te_4 is the same as its bulk state. The inability of surface ferromagnetism to open a gap in the topological surface state uncovers the novel complexity of MnBi_2Te_4 that may be responsible for the low quantum anomalous Hall temperature of exfoliated MnBi_2Te_4.Using the ab initio local force method, we investigate the formation mechanism of the helical spin structure in GdRu_2Si_2 and Gd_2PdSi_3. We calculate the paramagnetic spin susceptibility and find that the Fermi surface nesting is not the origin of the incommensurate modulation, in contrast to the naive scenario based on the Ruderman-Kittel-Kasuya-Yosida mechanism. We then decompose the exchange interactions between the Gd spins into each orbital component, and show that spin-density-wave type interaction between the Gd-5d orbitals is ferromagnetic, but the interaction between the Gd-4f orbitals is antiferromagnetic. selleck inhibitor We conclude that the competition of these two interactions, namely, the interorbital frustration, stabilizes the finite-Q structure.Hybrid quantum devices expand the tools and techniques available for quantum sensing in various fields. Here, we experimentally demonstrate quantum sensing of a steady-state magnon population in a magnetostatic mode of a ferrimagnetic crystal. Dispersively coupling the magnetostatic mode to a superconducting qubit allows for the detection of magnons using Ramsey interferometry with a sensitivity on the order of 10^-3 magnons/sqrt[Hz]. The protocol is based on dissipation as dephasing via fluctuations in the magnetostatic mode reduces the qubit coherence proportionally to the number of magnons.Ions in ionic liquids and concentrated electrolytes reside in a crowded, strongly interacting environment, leading to the formation of discrete layers of charges at interfaces and spin-glass structure in the bulk. Here, we propose a simple theory that captures the coupling between steric and electrostatic forces in ionic liquids. The theory predicts the formation of discrete layers of charge at charged interfaces. Further from the interface, or at low polarization of the electrode, the model outputs slowly decaying oscillations in the charge density with a wavelength of a single ion diameter, as shown by analysis of the gradient expansion. The gradient expansion suggests a new structure for partial differential equations describing the electrostatic potential at charged interfaces. We find quantitative agreement between the theory and molecular simulations in the differential capacitance and concentration profiles.To understand the nature of the brightest γ-ray binary system LS 5039, hard x-ray data of the object, taken with the Suzaku and NuSTAR observatories in 2007 and 2016, respectively, were analyzed. The two data sets jointly gave tentative evidence for a hard x-ray periodicity, with a period of ∼9 s and a period increase rate by ∼3×10^-10 s s^-1. Therefore, the compact object in LS 5039 is inferred to be a rotating neutron star, rather than a black hole. Furthermore, several lines of arguments suggest that this object has a magnetic field of several times ∼10^10 T, two orders of magnitude higher than those of typical neutron stars. The object is hence suggested to be a magnetar, which would be the first to be found in a binary. The results also suggest that the highly efficient particle acceleration process, known to be operating in LS 5039, emerges through interactions between dense stellar winds from the massive primary star, and u