Laser light induces giant current in topological material

Amazing stuff!

"... Since backscattering is the main dissipating process in electronics, topological insulators can carry electrical current with near-zero dissipation. ...
For physicists, zirconium pentatelluride (ZrTe5) is a particularly interesting topological material because it exists in a wide variety of topological phases. Indeed, depending on how it is configured, it can behave as a weak or strong topological insulator, a 3D quantum Hall state or a Dirac semimetal. In the latter phase, ZrTe5 exhibits exotic electron conduction behaviour thanks to the unique state of its crystal lattice and electronic structure, which protect electrons from backscattering ...
discovered that they could generate a huge current in ZrTe5 by exposing the material to laser light at terahertz frequencies. This current arises because light at these frequencies triggers vibrations, or phonons, in the material’s crystal lattice that distort its symmetry. ...

Universal topology control principle?

The researchers, who report their work in Nature Materials, note that phononic symmetry switching enables them to control the flow of electrons without using electric or magnetic fields. Such a fast, low-energy, symmetry-based switch was lacking until now ..." 

"... Our work suggests that this phononic terahertz symmetry switching leads to formation of Weyl points, whose chirality manifests in a transverse, helicity-dependent current, orthogonal to the dynamical inversion symmetry breaking axis, via circular photogalvanic effect. The temperature-dependent topological photocurrent exhibits several distinct features: Berry curvature dominance, particle–hole reversal near conical points and chirality protection that is responsible for an exceptional ballistic transport length of ~10 μm. ..."

That is a mouthful! This is almost hieroglyphics to me! 😄 

Laser light induces giant current in topological material – Physics World Researchers in the US have induced a huge and nearly dissipationless current in zirconium pentatelluride – a technologically important material that exhibits strong topological electronic effects – by illuminating it with laser light. 

Here is a link to the referenced paper:

A light-induced phononic symmetry switch and giant dissipationless topological photocurrent in ZrTe5