An international team of scientists has identified and characterized the material in which rare particles, the so-called three-point fermions, are formed. Experts expect them to play an important role in quantum computers. The study was published by the renowned journal Physical Review Letters.
researchers studied the ferroelectric material Germanium telluride (GeTe),
which is known, for example, as the active layer in rewritable DVDs or CDs. It
is in it that the phenomenon of the "triple point", ie a very unusual
crossing of three fermions, can be experimentally verified.
we distinguish thousands of particles, which we divide into two large groups
according to their behavior: fermions and bosons. Fermions can exist either as
individual particles, ie as electrons, protons, and neutrons or as so-called
quasiparticles. These are composed of many components but behave like a single
fermion particle. Fermions are characterized by intolerable behavior, where two
particles with the same rotation cannot occupy the same state and place. Either
four (Weyl) or two fermions (Dirac) can intersect," explains Ján Minár from the NTC
NTC scientists have predicted triple fermions. They can occur in different crystals
and only in special circumstances. In addition, for the first time ever,
experts were able to identify spin windings around triple fermions, ie their
internal magnetic moment. The study was published by the renowned journal
Physical Review Letters of the American Physical Society. The authors of its
theoretical part are scientists from the NTC, the experimental part is based on
experts from the Swiss Federal Institute of Technology in Lausanne in
cooperation with other contributors.
study confirms that the special symmetries available in crystals leads to the
existence of fermions that are not permitted as free particles,” says Professor Hugo Dil at the
Swiss Federal Institute of Technology in Lausanne. Laurent Nicolaï, who did
theoretical calculations in Ján Minář's group at the NTC Research Center
adds: "We expect these triple and other related fermions will play
an important role in future quantum computers, built on the basis of new
Czech side, the project was financed from the Operational Program of the
Ministry of Education, Youth and Sports - Research, Development and Education:
Support for Excellent Research Teams CZ.02.1.01 / 0.0 / 0.0 / 15_003 / 0000358.
Nicolaï, Juraj Krempaský, Martin Gmitra, Houke Chen, Mauro Fanciulli, Eduardo
B. Guedes, Marco Caputo, Milan Radović, Valentine V. Volobuev, Ondřej Caha,
Gunther Springholz, Jan Minár, J. Hugo Dil. Phys. Rev. Lett. 126, 206403, 17
May 2021. DOI: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.206403
of the theoretical part:
University of West Bohemia – NTC (New Technologies –
of the experimental part:
polytechnique fédérale de Lausanne ‐ EPFL
Univerzita P. J.
Šafárika v Košicích (Slovensko), Univerzita Tsinghua (Peking), CY Cergy Paris
University (Francie), Polská akademie věd, Národní technická univerzita „KhPI“
(Ukrajina), Masarykova univerzita (Česká republika), Univerzita Johanna Keplera
Swiss National Science Foundation (SNSF), Austrian Science
Fund (FWF), Ministry of Education, Youth and Sports of the Czech Republic,
Grant Agency of the Czech Republic (GAČR), Grant System for Internal Research,
Foundation for Polish Science (IRA EU Program), European Regional Development
Fund development (CEITEC Nano +)
Transition between Dirac, triple, and Weyl Fermions. The colours indicate the spin of the state. Credit: Hugo Dil (EPFL).
prof. Dr. Ján Minár