Graphene: new bridge between condensed matter physics and quantum electrodynamics

TL;DR

Graphene serves as a unique platform connecting condensed matter physics and quantum electrodynamics, revealing relativistic phenomena like Zitterbewegung, Klein paradox, and vacuum polarization that influence its electronic properties.

Contribution

This paper highlights how graphene's relativistic-like electronic behavior bridges condensed matter physics and QED, providing new insights into quantum phenomena in two-dimensional materials.

Findings

Graphene exhibits relativistic charge carrier dynamics.

Relativistic effects explain graphene's minimum conductivity.

Quantum phenomena like Klein paradox are observed in graphene.

Abstract

Graphene is the first example of truly two-dimensional crystals - it's just one layer of carbon atoms. It turns out to be a gapless semiconductor with unique electronic properties resulting from the fact that charge carriers in graphene demonstrate charge-conjugation symmetry between electrons and holes and possess an internal degree of freedom similar to ``chirality'' for ultrarelativistic elementary particles. It provides unexpected bridge between condensed matter physics and quantum electrodynamics (QED). In particular, the relativistic Zitterbewegung leads to the minimum conductivity of order of conductance quantum $e^2/h$ in the limit of zero doping; the concept of Klein paradox (tunneling of relativistic particles) provides an essential insight into electron propagation through potential barriers; vacuum polarization around charge impurities is essential for understanding of high electron mobility in graphene; index theorem explains anomalous quantum Hall effect.