Researchers from the National University of Singapore researchers have developed an approach to account for the effect of dynamical electron-electron interactions when predicting the energy levels in valleytronic materials in the presence of a magnetic field.

The researchers predicted that Landau levels belonging to different valleys in a two-dimensional (2D) valleytronic material, monolayer tungsten diselenide (WSe₂), can be aligned at a critical magnetic field. The alignment of distinct entities, such as two laser beams, or two pillars, is a common goal in many fields of science and engineering. In the more exotic world of quantum mechanics, the alignment of quantized electronic levels can enable the creation of particles called pseudo-spinors that are useful for quantum computing applications.

Researchers from the Indian Institute of Technology Bombay (IIT Bombay) have proposed a device structure for a valley polariser which is robust, all-electrical, and can be seamlessly integrated with modern electronics. The device can be fabricated using existing fabrication techniques.

Image

The device is based on 2D-Xene materials. A single-layer of 2-D Xene is used as the charge carrying channel. A terminal called a gate controls the electric current flowing through the channel, similar to how a gate controls the current in the modern transistor design. The gate structure, which is also used to create the valley separation, sandwiches the 2-D Xene ribbon.

Researchers from Rice University suggest that growing graphene sheets on curved surface may be a useful technique to create valleytronics devices.

The peaks and valleys in the resulting "deformed" graphene sheet would create channels that will feature small magnetic fields. It will also be a way to achieve a Hall Effect, useful for valleytronics devices.

Researchers from the University of Oldenburg, managed to create a three-atoms-thick structure that emits laser-like light, at room temperature, for the first time. The researchers believe that coherent light emission from ultathin crystals could enable valleytronics devices in the future.

To create the light, the researchers used exciton-polaritons particles, formed from the strong interaction between confined photons and electrons. The structure itself is made from a single-layer of a WSe₂ crystal, that sits on top of a hBN 2D layer. The idea is that the exciton-polaritons are created in a trap in the WSe₂ and then captured and reflected by two distributed Bragg reflectors (DBRs) that act as mirrors.

Researchers from Germany (Max-Born Institute) and India (IIT Bombay) have shown that it is possible to realize a valleytronics device in pristine graphene.

Graphene (and other graphene-like systems) feature an extra degree of electron freedom, or valley pseudo-spin. This has interesting potential in valleytronics applications, but the implementation of valleytronics ideas has been so far limited to gapped graphene-like semiconducting 2D materials, most commonly transition metal dichalcogenides, and has never been attempted in pristine graphene, because graphene monolayers have zero bandgap, zero Berry curvature, and thus nearly identical valleys,.

Scientists from several research institutes in Germany and the UK have demonstrated that few-cycle linearly polarized pulses can induce a high degree of valley polarization.

The mechanism to induce such polarization does not rely on the optical selection rules, and therefore can be in principle used in inversion symmetric materials, such as TMD bilayers or graphene. This could enable the design of ultrafast valleytronic devices.

Researchers from Sweden's Uppsala university and from UK's Element Six have demonstrated electrical valley control in 3D dual-gate diamond field-effect transistors.

The team has fabricated valley transistors on single-crystalline diamond plates with ultra-low nitrogen impurity concentrations. A dual-gate configuration was used to gain a high degree of freedom of the control of the valley currents. The control of location and time of the valley-polarized currents was achieved by adding multiple drain electrodes.

Researchers from ETH Zurich and Aalto University showed that sandwiching two slightly rotated layers of graphene between a ferromagnetic insulator provides a unique setting for new electronic states.

Researchers from Rice University and Texas A&M University have discovered that a 2D derivative of perovskite has a good potential for valleytronics applications.

The researchers synthesized a layered compound of cesium, bismuth and iodine that is able to store the valley states of electrons, but only in the structure's odd layers. These bits can be set with polarized light, and the even layers appear to protect the odd ones from the kind of field interference that bedevils other perovskites, according to the researchers.

Researchers from Cornell University managed to control the valley (orbital angular momentum) of electrons in a material by using electrical inputs to manipulate the magnetism of an adjacent material.