Scientists have obtained the clearest image of the electron particles that make up the Quantum Spin Liquid (QSL).

For the first time, scientists have captured an image of how electrons in QSL decay into spin-like particles, or spinons, and charge-like particles called chargons.

This achievement will help in the development of ultrafast quantum computers and energy efficient superconductors.

Other researchers have seen various traces of this phenomenon, but we have a real picture of the state in which the spinon is. This is something new.

Mike Crommy, Professor of Physics and Senior Research Fellow at Lawrence Berkeley National Laboratory
Spinons can be called ghost particles, since they can be occasionally observed, but it is difficult to prove the very fact of their existence. Using a new method, scientists have provided one of the best evidence for the existence of spinons to date.

In a quantum spin liquid or QSL, spinons move freely, transferring heat and rotation, but without electric charge. Scientists have previously looked for them relying on thermal signature-based methods.

In the new work, the authors grew single-layer samples of tantalum diselenide (1T-TaSe2) just three atoms thick from an advanced light source from Berkeley Laboratories (ALS). This material belongs to a class of materials called transition metal dichalcogenides (TMDC).

The team then characterized the thin films using angle-resolved photoemission spectroscopy, a technique commonly using X-rays. Next, using scanning tunneling microscopy (STM), the researchers injected electrons from a metal needle into a tantalum diselenide TMDC sample.

After that, the authors found out that when an electron is injected into the QSL from the tip of the STM, it decays into two different particles inside the QSL:

  • spinons,
  • charges.

Spinon particles ultimately carry spin separately, while charges separately carry an electric charge.

As a result, the STM / STS image shows the charges solidifying in place, forming what scientists call the Star of David charge density wave. Meanwhile, the spinons are separated from the immobilized charges and move freely through the material.