Researchers from the University of California, Riverside managed not only to observe, but also to interact with dark trions. To do this, they applied a voltage to a wafer of semiconductor, ultrapure tungsten diselenide, one atom thick. By controlling the charge density, scientists were able to turn positive trions into negative ones, thereby showing the possibility of creating a mechanism to control them.
Trions, from the word “three”, in modern physics are called constituent elements of charged particles. If you take two electrons and one “hole”, empty space with a positive charge, you get a negative trion. Two holes and one electron is a positive trion. In “bright” trions, the particle spins are opposite, so they easily combine and emit a lot of energy, such are easier to notice. The “dark” trions have the same particle spins, they emit little, and therefore their lifespan is 100 times longer than that of bright trions.
It is the long lifespan that made dark trions interesting for scientists, as this allows them to be used for practical purposes. Trion behaves like a charged particle, but its structure is much more complex than a single electron and amenable to correction. This means that trion can encode many times more information than a simple binary code on electrons, with the same movement speed in semiconductors. And this promises a multiple increase in data transfer speed and a revolution in digital technologies in general.
Until recently, scientists were only interested in bright trions, because they are easy to spot. The discovery of Californian physicists radically changes everything – if they manage to build a prototype transmitter on long-lived dark trions, the world will be on the verge of a new era. I wonder what it will be called – “the era of Trionism”?