Collider made for quasiparticles

Science News : Particle colliders have been a standard part of the physicist’s toolkit for around 100 years, with different kinds of colliders being created for different kinds of particles. Now, Rupert Huber of the University of Regensburg in Germany and his colleagues have developed a collider that smashes electrons into quasiparticles known as holes. A hole is a void that is formed by the absence of an electron in a sea of electrons and that behaves like a particle. Huber’s group created pairs of electrons and holes in tungsten diselenide with a short pulse of light and then applied an oscillating electric field. The field pulled the electrons and holes apart and then slammed them back together at several thousand kilometers per second. The collision results in the emission of light, which Huber’s team analyzed to measure the energy required to separate the electron–hole pair. Huber says the information could be useful for improving solar cells, which collect the energy from the separation of electron–hole pairs generated by sunlight.