In
condensed matter physics
Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter, especially the solid and liquid State of matter, phases, that arise from electromagnetic forces between atoms and elec ...
, semi-Dirac fermions are a class of
quasiparticle
In condensed matter physics, a quasiparticle is a concept used to describe a collective behavior of a group of particles that can be treated as if they were a single particle. Formally, quasiparticles and collective excitations are closely relate ...
s that are
fermionic
In particle physics, a fermion is a subatomic particle that follows Fermi–Dirac statistics. Fermions have a half-integer spin (spin , spin , etc.) and obey the Pauli exclusion principle. These particles include all quarks and leptons and all c ...
with the unusual property that their energy
dispersion relation
In the physical sciences and electrical engineering, dispersion relations describe the effect of dispersion on the properties of waves in a medium. A dispersion relation relates the wavelength or wavenumber of a wave to its frequency. Given the ...
changes from quadratic to linear dependent on their direction of motion. Their theoretical properties have been studied prior to their observation in 2024.
Their first observation in a solid was in
zirconium silicon sulfide (ZrSiS), a
topological semi-metal, and was published in 2024.
See also
*
Dirac fermion
In physics, a Dirac fermion is a spin-½ particle (a fermion) which is different from its antiparticle. A vast majority of fermions fall under this category.
Description
In particle physics, all fermions in the standard model have distinct antipar ...
References
Fermions
Quasiparticles
External links
* David Nield
Physicists Find Particle That Only Has Mass When Moving in One Direction ScienceAlert, 14 December 2024.
{{improve categories, date=December 2024