Spintronics

Researchers from Penn State, University of Oxford, Zhejiang University, Diamond Light Source and the University of North Texas have demonstrated a new route to Ising‑type superconductivity in a lightweight, low‑dimensional material by combining quantum confinement with strong interfacial hybridization. Using plasma‑free confinement epitaxy aided by a carbon buffer layer, they synthesized a gallium trilayer sandwiched between graphene and a 6H‑SiC(0001) substrate, creating a two‑dimensional superconducting channel where Cooper pairs are stabilized against in‑plane magnetic fields well beyond the Pauli paramagnetic limit.

In this structure, three atomic layers of gallium are confined between a silicon carbide (6H‑SiC) substrate below and a graphene capping layer above. The graphene both protects the gallium from oxidation and defines the top interface, while the SiC substrate provides a rigid template and a source of strong interfacial coupling. Electrical transport measurements show that the system becomes superconducting at low temperatures, with an in‑plane upper critical magnetic field of about 21.98 T at 400 mK, which is approximately 3.38 times the conventional Pauli paramagnetic limit for this material.

A recent review by researchers at the Catalan Institute of Nanoscience and Nanotechnology (ICN2) and the Universitu of Barcelona provides an overview of an emerging class of carbon nanomaterials: nanoporous graphenes (NPGs). The work highlights how these structures, conceived as two-dimensional arrays of laterally bonded graphene nanoribbons (GNRs), could transform the future of nanoelectronics and spintronics.

Built through bottom-up on-surface synthesis, this approach enables atomic precision in assembling carbon nanoarchitectures, offering tunable electronic and magnetic properties. While GNRs have long been central to nanoelectronics due to their semiconducting and π-conjugated characteristics, NPGs extend their functionality by providing an intrinsic platform to regulate electronic coupling between adjacent ribbons. This feature allows for the controlled emergence of quantum anisotropy, where electrical conduction varies according to direction.

Researchers from Empa, Chinese Academy of Sciences, the Chinese University of Hong Kong and Max Planck Institute for Polymer Research have developed a hybrid system in which porphyrins are attached to graphene nanoribbons (GNRs) in a precise and well-defined manner. 

Image credit: Credit: Swiss Federal Laboratories for Materials Science and Technology

Graphene nanoribbons with zigzag edges are promising materials for spintronic devices, owing to their tunable bandgaps and spin-polarized edge states. Porphyrins offer complementary optoelectronic benefits. In the new system, a graphene ribbon just one nanometer wide with zigzag edges is used as a molecular wire, along which porphyrin molecules are docked at perfectly regular intervals, alternating between the ribbon’s left and right sides.

A University of Manchester team of scientists has reported a 'significant milestone in the field of quantum electronics' with their latest study on spin injection to graphene. The paper outlines advancements in spintronics and quantum transport.

Spin transport electronics, or spintronics, represents a revolutionary alternative to traditional electronics by utilizing the spin of electrons rather than their charge to transfer and store information. This method promises energy-efficient and high-speed solutions that exceed the limitations of classical computation, for next generation classical and quantum computation. The Manchester team, led by Dr. Ivan Vera-Marun, has fully encapsulated monolayer graphene in hexagonal boron nitride, an insulating and atomically flat 2D material, to protect its high quality. By engineering the 2D material stack to expose only the edges of graphene, and laying magnetic nanowire electrodes over the stack, they successfully form one-dimensional (1D) contacts.

Researchers from the National University of Singapore (NUS), working with teams from University of California, Kyoto University and others, have reported a breakthrough in the development of next-generation graphene-based quantum materials, opening new horizons for advancements in quantum electronics.

An atomic model of the Janus graphene nanoribbons (left) and its atomic force microscopic image (right). Image credit: NUS
 

The innovation involves a novel type of graphene nanoribbon (GNR) named Janus GNR (JGNR). The material has a unique zigzag edge, with a special ferromagnetic edge state located on one of the edges. This unique design enables the realization of one-dimensional ferromagnetic spin chain, which could have important applications in quantum electronics and quantum computing.

Researchers from the National University of Singapore (NUS), and Czech Academy of Sciences recently developed a new design concept for creating next-generation carbon-based quantum materials, in the form of a tiny magnetic nanographene with a unique butterfly-shape hosting highly correlated spins. This new design has the potential to accelerate the advancement of quantum materials which are pivotal for the development of quantum computing technologies.

A visual impression of the magnetic “butterfly” hosting four entangled spins on “wings” (left) and its corresponding atomic-scale image obtained using scanning probe microscopy (right). Image credit: NUS

Magnetic nanographene, a tiny structure made of graphene molecules, exhibits remarkable magnetic properties due to the behavior of specific electrons in the carbon atoms’ π-orbitals. By precisely designing the arrangement of these carbon atoms at the nanoscale, control over the behavior of these unique electrons can be achieved. This renders nanographene highly promising for creating extremely small magnets and for fabricating fundamental building blocks needed for quantum computers, called quantum bits or qubits.

Researchers from Helmholtz-Zentrum Dresden-Rossendorf, Universität Duisburg-Essen, CENTERA Laboratories, Indian Institute of Technology, University of Maryland and the U.S. Naval Research Laboratory have used graphene disks to demonstrate light-induced transient magnetic fields from a plasmonic circular current with extremely high efficiency. 

The effective magnetic field at the plasmon resonance frequency of the graphene disks (3.5 THz) is evidenced by a strong ( ~ 1°) ultrafast Faraday rotation ( ~ 20 ps). In accordance with reference measurements and simulations, the team estimated the strength of the induced magnetic field to be on the order of 0.7 T under a moderate pump fluence of about 440 nJ cm⁻².

Researchers at the National University of Singapore (NUS), University of Science and Technology of China and the National Institute for Materials Science in Japan have developed a way to induce and directly quantify spin splitting in two-dimensional materials.

Using this concept, they have experimentally achieved large tunability and a high degree of spin-polarization in graphene. This research achievement can potentially advance the field of two-dimensional (2D) spintronics, with applications for low-power electronics.

Researchers from Germany's RWTH Aachen University, Forschungszentrum Jülich and Japan's National Institute for Materials Science (NIMS) have found that bilayer graphene allows the realization of electron–hole double quantum dots that exhibit near-perfect particle–hole symmetry. Moreover, They showed that particle–hole symmetric spin and valley textures lead to a protected single-particle spin-valley blockade that will allow robust spin-to-charge and valley-to-charge conversion, which are essential for the operation of spin and valley qubits.

Quantum dots in semiconductors such as silicon or gallium arsenide are considered great candidates for hosting quantum bits in future quantum processors. The recent study essentially shows that bilayer graphene has even more to offer than other materials. The double quantum dots the researchers have created are characterized by a nearly perfect electron-hole-symmetry that allows a robust read-out mechanism – one of the necessary criteria for quantum computing. 

A research team at Chalmers University of Technology, Lund University and Uppsala University in Sweden have managed to create a device made of a two-dimensional magnetic quantum material that can work in room temperature. Quantum materials with magnetic properties are believed to pave the way for ultra-fast and considerably more energy efficient computers and mobile devices, but until now, these types of materials tended to only work in extremely cold temperatures. 

The group of researchers has been able to demonstrate, for the very first time, a new two-dimensional magnetic material-based device at room temperature. They used an iron-based alloy (Fe₅GeTe₂) with graphene which can be used as a source and detector for spin polarized electrons. The breakthrough is believed to enable a range of technical applications in several industries as well as in our everyday lives.