Spin-½

About: Spin-½ is a research topic. Over the lifetime, 40423 publications have been published within this topic receiving 796639 citations.

Spin structure of the Shockley surface state on Au ( 111 )

Abstract: The free-electron like surface state on the (111) surface of gold shows a splitting into two parabolic subbands induced by the spin orbit interaction. Spin-resolved high-resolution photoemission experiments performed with a full three-dimensional spin polarimeter provide a detailed image of the resulting spin structure. In particular, spin-resolved momentum distribution maps show that the spin vector lies in the surface plane and is perpendicular to the momentum of the electrons as expected in a free-electron model. This method of measuring the spin structure of a two-dimensional electron gas allows the observation of the direction of electric fields as probed by the electrons. Although the energy splitting can only be understood as a consequence of strong atomic electric fields, no modulation of the spin direction due to these fields is detected.

Quantum Description of High‐Resolution NMR in Liquids

Abstract: 1 Elementary description of NMR 2 Epitome of quantum mechanics 3 Spin and magnetic moment 4 Quantum statistical mechanics 5 Quantum description of NMR 6 Generalities on 2D spectroscopy 7 J Spectroscopy 8 Shift correlation spectroscopy 9 Multiple quantum coherence and applications 10 Fundamentals of relaxation theory

Strong interplay between stripe spin fluctuations, nematicity and superconductivity in FeSe

Abstract: In iron-based superconductors the interactions driving the nematic order (that breaks four-fold rotational symmetry in the iron plane) may also mediate the Cooper pairing. The experimental determination of these interactions, which are believed to depend on the orbital or the spin degrees of freedom, is challenging because nematic order occurs at, or slightly above, the ordering temperature of a stripe magnetic phase. Here, we study FeSe (ref. )-which exhibits a nematic (orthorhombic) phase transition at Ts = 90 K without antiferromagnetic ordering-by neutron scattering, finding substantial stripe spin fluctuations coupled with the nematicity that are enhanced abruptly on cooling through Ts. A sharp spin resonance develops in the superconducting state, whose energy (∼4 meV) is consistent with an electron-boson coupling mode revealed by scanning tunnelling spectroscopy. The magnetic spectral weight in FeSe is found to be comparable to that of the iron arsenides. Our results support recent theoretical proposals that both nematicity and superconductivity are driven by spin fluctuations.

Controlling the Competition between Optically Induced Ultrafast Spin-Flip Scattering and Spin Transport in Magnetic Multilayers

Abstract: The study of ultrafast dynamics in magnetic materials provides rich opportunities for greater fundamental understanding of correlated phenomena in solid-state matter, because many of the basic microscopic mechanisms involved are as-yet unclear and are still being uncovered. Recently, two different possible mechanisms have been proposed to explain ultrafast laser induced magnetization dynamics: spin currents and spin-flip scattering. In this work, we use multilayers of Fe and Ni with different metals and insulators as the spacer material to conclusively show that spin currents can have a significant contribution to optically induced magnetization dynamics, in addition to spin-flip scattering processes. Moreover, we can control the competition between these two processes, and in some cases completely suppress interlayer spin currents as a sample undergoes rapid demagnetization. Finally, by reversing the order of the Fe=Ni layers, we experimentally show that spin currents are directional in our samples, predominantly flowing from the top to the bottom layer.

Distinguishing a Majorana zero mode using spin-resolved measurements

Abstract: One-dimensional topological superconductors host Majorana zero modes (MZMs), the nonlocal property of which could be exploited for quantum computing applications. We use spin-polarized scanning tunneling microscopy to show that MZMs realized in self-assembled Fe chains on the surface of Pb have a spin polarization that exceeds that stemming from the magnetism of these chains. This feature, captured by our model calculations, is a direct consequence of the nonlocality of the Hilbert space of MZMs emerging from a topological band structure. Our study establishes spin-polarization measurements as a diagnostic tool to distinguish topological MZMs from trivial in-gap states of a superconductor.