What Are Dirac Electrons and Their Role in Solid-State Physics?

[Pion]

What is a Dirac eletron ?
I just take this concept when reading a news in a physics page.
Thank you for helping me out.

 

[dextercioby]

It's an electron described by the Dirac's equation of 1928.
http://rspa.royalsocietypublishing.org/content/117/778/610 + http://rspa.royalsocietypublishing.org/content/118/779/351

I think both articles are free to download.

 

[vanhees71]

The electron is described within the standard model with help of a quantum field called a Dirac-spinor field. Sometimes people write in a bit sloppy way about "Dirac electrons", when they want to emphasize that they look at a theory or model that describes electrons with the help of quantized Dirac-spinor fields. Of course there's only one type of particle, called an electron: It's uniquely specified by its mass ($\sim 511 \; \text{keV}/c^2$), charge (1 negative elementary charge), and spin (1/2) as well as the fact that it is a lepton taking part in the electromagnetic and the weak interactions but not (directly) in the strong interaction.

 

[R.P.]

All electrons are described by Dirac spinor fields at a fundamental elementary-particle level, so in that sense they are all Dirac electrons. But one often sees the term "Dirac electron" used in a different sense in solid-state physics, where one often talks in terms of "quasi particles" instead of elementary particles such as an electron, in order to take into account the interactions with the crystal lattice. It seems that "Dirac electrons" are quasi particles that behave as massless electrons. See articles on graphene and topological insulators, for example.