Diracsemimetalen

Diracsemimetalen, also known as Dirac semimetals, are a class of quantum materials in which the conduction and valence bands touch at discrete points in momentum space. Around these points the electronic dispersion is linear, resembling the relativistic Dirac equation, and the quasiparticles behave as massless Dirac fermions. This linear dispersion results in high carrier mobility and unusual magneto‑transport phenomena such as large, non‑saturating magnetoresistance and the chiral anomaly. The crystal symmetry and time‑reversal invariance protect the Dirac points in many of these materials, which are typically found in three‑dimensional systems such as Na₃Bi, Cd₃As₂, and Bi₂Se₃ under specific conditions.

The discovery of Dirac semimetals began with theoretical predictions of 2D graphene and was extended to 3D systems in the early 2010s. Experimental confirmation came from angle‑resolved photoemission spectroscopy, which mapped the linear bands intersecting at the Dirac points. The robustness of the Dirac fermions to disorder makes these materials attractive for electronic and spintronic applications, including potential use in quantum computing and high‑frequency devices.

Research into Diracsemimetalen also links to adjacent fields such as Weyl semimetals and topological insulators, as symmetry breaking in Dirac systems can transform them into Weyl systems with separated chirality. Continued study focuses on tuning the Fermi level, exploring pressure and chemical substitution effects, and understanding the interplay between electronic correlations and Dirac physics.