Light‐Element Superconductors

Abstract

Superconductors are one of the most surprising and fascinating specimens of condensed matter: they are perfect conductors, with current flowing without resistance, and perfect diamagnets, which expel completely any magnetic fields. Superconductivity was first discovered over 100 years ago, yet a complete understanding of its mechanisms is still lacking. Meanwhile, about every second element in the periodic table and hundreds of compounds have been found to superconduct, at ambient or elevated pressures. Many of these compounds involve the light elements—sometimes merely as electron donors, providing charge carriers to semiconducting or semimetallic materials, and sometimes as integral part of shaping unique materials with respectable superconducting transition temperatures. In this article, we will discuss the superconducting properties of the light elements and the huge effects of external pressure in some of them, and the most prominent examples of light element‐containing compounds, such as magnesium diboride, intercalated carbon compounds, and predicted high‐pressure compounds involving a lot of the lightest element, hydrogen.