Researchers use light to control magnetic fields at nanoscale

A correlated phase that  electrons can take on is magnetic order, in which they align their spin in the same direction. Traditionally, the ability to manipulate magnetic order within a 2D semiconductor has been limited; scientists have used external magnetic fields, which limit technological integration and potentially conceal interesting phenomena. Now, researchers from the University of Chicago’s Pritzker School of Molecular Engineering (PME) have discovered how to use nanoscale, low-power laser beams to precisely control magnetism within a 2D semiconductor. Their approach could have implications for both studying the emergence of the correlated phase as well as designing new optoelectronic and spintronic devices.

“The fact that we can now use light to manipulate electrons in this way means we have unprecedented control over this magnetic order,” said Asst. Prof. Alex High, the senior author of the new work.

Read the full story Posted: Oct 08,2022

Researchers deepen understanding of 1D spin chains

Researchers from Oak Ridge National Laboratory, Helmholtz-Zentrum Berlin (HZB) and University of Amsterdam have used inelastic neutron scattering and methods of integrability to experimentally observe and theoretically describe a local, coherent, long-lived, quasiperiodically oscillating magnetic state emerging out of the distillation of propagating excitations following a local quantum quench in a Heisenberg antiferromagnetic chain.

This “quantum wake” displays similarities to Floquet states, discrete time crystals and nonlinear Luttinger liquids. The team also showed how this technique reveals the non-commutativity of spin operators, and is thus a model-agnostic measure of a magnetic system’s “quantumness.”

Read the full story Posted: Oct 04,2022

Researchers find Fermi arcs in a 2D magnet

Researchers from Germany's Forschungszentrum Juelich have reported an exotic electronic state, so-called Fermi Arcs, for the first time in a 2D material. Finding Fermi arcs in such a material may provide a link between novel quantum materials and their potential applications in a new generation of spintronics and quantum computing. 

The newly demonstrated Fermi arcs represent special—arc-like—deviations from the so-called Fermi surface. The Fermi surface is used in condensed matter physics to describe the momentum distribution of electrons in a metal. Normally, these Fermi surfaces represent closed surfaces. Exceptions such as the Fermi arcs are very rare and often are associated with exotic properties like superconductivity, negative magnetoresistance and anomalous quantum transport effects.

Read the full story Posted: Sep 28,2022

Researchers report chiral oxide catalysts that align electron spin

A University of Münster, University of Duisburg-Essen and University of Pittsburgh research team recently set out to advance the systematic development of spin-selective catalyst materials. To this end, the researchers related the catalytic activity of various inorganic spin-polarizing materials to direct measurements of spin selectivity. The focus is on oxide materials which were purposely grown with a chiral structure. In addition, the researchers also wanted to investigate the origin of spin polarization in these chiral materials. 

The team first examined chiral oxide catalysts—consisting in this case of thin, chiral copper oxide layers on a thin film of gold. The data measured showed that the spin polarization of the electrons depends on which of these layers the electrons come from. The team considers two effects to be responsible for this: the chirality-induced spin selectivity (CISS) effect and the magnetic arrangement in the chiral layers. The results are to help in the future production of spin-selective catalytic oxide materials, thus improving the efficiency of chemical reactions.

Read the full story Posted: Sep 26,2022

Researchers detect and map non-linear spin waves

Researchers from Germany's Martin Luther University Halle-Wittenberg (MLU) have demonstrated that strong alternating magnetic fields can be used to generate a new type of spin wave. This is the first time this was accomplished as the phenomenon was previously only theoretically predicted. Thee team reported on their work and provided the first microscopic images of these spin waves.

The basic idea of spintronics is to use a special property of electrons (spin) for various electronic applications. The Spin is the intrinsic angular momentum of electrons that produces a magnetic moment. Coupling these magnetic moments creates the magnetism that could ultimately be used in information processing. When these coupled magnetic moments are locally excited by a magnetic field pulse, this dynamic can spread like waves throughout the material. These are referred to as spin waves or magnons.

Read the full story Posted: Sep 16,2022

Researchers pair CrSBr magnons with excitons to "see" spins

Researchers from Columbia University, the University of Washington, New York University, and Oak Ridge National Laboratory have shown that magnons in CrSBr can pair up with another quasiparticle called an exciton, which emits light, offering the researchers a means to “see” the spinning quasiparticle.

As they perturbed the magnons with light, they observed oscillations from the excitons in the near-infrared range, which is nearly visible to the naked eye. “For the first time, we can see magnons with a simple optical effect,” said Xiaoyang Zhu from Columbia University .  

Read the full story Posted: Sep 10,2022

Researchers use QD electrodes to examine spin transport properties of DNA sensors

Scientists from India's B. P. Poddar Institute of Management & Technology, Maulana Abul Kalam Azad University of Technology and Meghnad Saha Institute of Technology, collaboration with the University of Western Australia, have used iron (Fe) quantum dot (QD) electrodes to determine the spin transport properties and quantum scattering transmission characteristics of DNA sensors at room temperature. 

Spintronics has shown great potential for the development of devices that require low power for operation, high density and high speed processing, all of which are ideal for electronic memory devices. These properties are used in optoelectronic devices, mainly for circularly polarized light. Interestingly, spintronics is also applied in a semiconductor tunnel junction.

Read the full story Posted: Sep 08,2022

Researchers investigate spin currents in chromium trihalides

Scientists have been looking for efficient methods to generate spin current. The photogalvanic effect, a phenomenon characterized by the generation of DC current from light illumination, is particularly useful in this regard. Studies have found that a photogalvanic spin current can be generated similarly using the magnetic fields in electromagnetic waves. However, there's a need for candidate materials and a general mathematical formulation for exploring this phenomenon.

Now, Associate Professor Hiroaki Ishizuka from Tokyo Institute of Technology (Tokyo Tech), along with his colleague Masahiro Sato, addressed these issues. In their recent study, they presented a general formula that can be used to calculate the photogalvanic spin current induced by transverse oscillating magnetic excitations. They then used this formula to understand how photogalvanic spin currents arise in bilayer chromium (Cr) trihalide compounds, namely chromium triiodide (CrI3) and chromium tribromide (CrBr3).

Read the full story Posted: Sep 05,2022

Researchers gain new insights into the interaction of topological insulators

An international team of researchers has succeeded in understanding, for the first time, how the topological properties of multilayer systems of Tungsten di-telluride (WTe2) can be changed systematically by means of scanning tunneling microscopy.

WTe2 has been found to be a promising material for the realization of topological states, which are regarded as the key to novel spintronics devices and quantum computers of the future due to their unique electronic properties. 

Read the full story Posted: Aug 26,2022