Topological control by tuning structural chirality

July 16, 2020

Chiral crystals that have a distinct handedness have recently emerged as one of  the most exciting new classes of topological materials. An international research team from institutions in Germany, Switzerland, United Kingdom, and China has now demonstrated that their crystal handedness directly determines how quasiparticles propagate and scatter at impurities in such materials. The study, published in the journal Nature Communications, represents a significant advance towards novel chiral electronic devices.

Top panels:crystal structure for both PdGa enantiomers; bottom panels: quasi particle interference pattern developing around native crystal defects

A chiral object cannot be superimposed onto its mirror image – a notable example, your own hands. Chirality plays a critical role in many branches of sciences, from biology to chemistry. The interaction between molecules or biological components depends on their chirality, thereby affecting drug development, for example. The optical and transport properties of solid-state systems can be strongly influenced by chirality and even the ground states of such systems may be chiral. For example, magnetic materials can spontaneously form chiral non-collinear spin-textures such as skyrmions or anti-skyrmions.

More recently, scientists predicted entirely new classes of quasiparticles in topological materials that are chiral.  These predictions were confirmed by detailed inspections of their electronic structure using angle resolved photoemission experiments. These materials include the binary compounds CoSi, RhSn, and PtAl that have a chiral crystal structure (space group, 198).  Clear signatures of chiral electronic behavior have now been revealed by physicists at the Max Plank Institute of Microstructure Physics, in Halle, Germany in one of these materials, the chiral semimetal PdGa.

More information you can find here.

Go to Editor View