topological insulator tagged posts

Rendering of the electronic device in which Majorana particles were observed. The device is made up of a superconductor (blue bar) and a magnetic topological insulator (gray strip). The Majorana particles result in transport channels (shown in red, pink, blue and yellow) in the electronic device. Credit: Courtesy UCLA

U.S. Army-funded researchers at ULCA have found a proverbial smoking gun signature of the long sought-after Majorana particle, and the find, they say, could block intruders on sensitive communication networks...

The aluminum plates were attached to the topological insulator using platinum. The picture (scale bar: 200?nm) shows one of the devices used in the experiment. Because of the stress, induced by various cool downs, a clear buckling feature appears in the nanogap of the device. This modification is causing the characteristics of the superconducting pairs of electron to vary in different directions, a signature of unconventional superconductivity. Credit: Thilo Bauch and Floriana Lombardi/Chalmers University of Technology

They have probably succeeded in creating a topological superconductor. With their insensitivity to decoherence what are known as Majorana particles could become stable building blocks of a quantum computer...

Spin injection and helicity control of surface spin photocurrent in a three dimensional topological insulator. Nature Communications, 2017; 8: 15401 DOI: 10.1038/ncomms15401

A discovery of how to control and transfer spinning electrons paves the way for novel hybrid devices that could outperform existing semiconductor electronics. In a study researchers at Linkoping University in Sweden demonstrate how to combine a commonly used semiconductor with a topological insulator. Just as the Earth spins around its own axis, so does an electron, in a clockwise or counter-clockwise direction. “Spintronics” is the name used to describe technologies that exploit both the spin and the charge of the electron. Current applications are limited, and the technology is mainly used in computer hard drives...

Artist’s rendition of optically-defined quantum circuits in a topological insulator. Credit: Peter Allen

In contrast to using advanced nanofabrication facilities based on chemical processing of materials, this flexible technique allows for rewritable ‘optical fabrication’ of devices. The electrons in topological insulators have unique quantum properties useful for developing low-power spin-based electronics and quantum computers. However, making even the simplest experimental circuits with these materials has proved difficult because traditional semiconductor engineering techniques tend to destroy their fragile quantum properties. Even a brief exposure to air can reduce their quality.

The researchers report the discovery of an optical effect that allows them to “tune” the energy of electro...