Magnetic, transport, and optical properties of monolayer copper oxides

TLDR

These antiferromagnetic insulators with large Heisenberg exchange energies become high‑temperature superconductors upon carrier doping, and the study focuses on pure and lightly doped materials while also addressing magnetism in the superconducting phase. The authors review experimental results on La₂CuO₄ and Nd₂CuO₄, focusing on the undoped CuO₂ layer and how magnetic, optical, and transport properties evolve with carrier addition. Large single crystals enable neutron scattering and anisotropic optical, transport, and magnetization measurements, which the authors use to review experimental results on La₂CuO₄ and Nd₂CuO₄ and their weakly coupled CuO₂ layers.

Abstract

The authors review the results of a wide variety of experiments on materials such as ${\mathrm{La}}_{2}{\mathrm{CuO}}_{4}$ and ${\mathrm{Nd}}_{2}{\mathrm{CuO}}_{4}$ that contain weakly coupled ${\mathrm{CuO}}_{2}$ layers. These materials are antiferromagnetic insulators with very large Heisenberg exchange energies, which become high-temperature superconductors when charge carriers are added to the ${\mathrm{CuO}}_{2}$ layers. The growth of large single crystals has made it possible to carry out neutron scattering, as well as anisotropic optical, transport, and magnetization measurements. The properties of the undoped ${\mathrm{CuO}}_{2}$ layer are reviewed, and the evolution of magnetic, optical, and transport properties with the addition of charge carriers is discussed. The emphasis is on the pure and lightly doped materials, although the magnetism in the superconductors is discussed.