Related Experiment Video
Updated: May 30, 2026

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
Q-dependence of spin excitations in high-T(C) cuprates from spin-phonon coupling
1Département de Physique de la Matière Condensée, University of Geneva, 24 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.
Abstract:
An understanding of spin excitations in cuprates is essential since the mechanism of high-T(C) superconductivity might be linked to spin fluctuations. Band calculations for 'one-dimensional' unit cells of La(2)CuO(4) show larger coupling (spin-phonon coupling, SPC) between anti-ferromagnetic spin waves and O-phonons than for Cu- or La-phonons. When this result is applied to a two-dimensional, free-electron like band, it leads to an 'hourglass' shape of the spin excitation spectrum, as in recent experiments. Isotope shifts and doping dependences of the excitations are discussed.
Related Concept Videos
Valence Bond Theory
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
NMR Spectroscopy: Spin–Spin Coupling
Spin–Spin Coupling Constant: Overview
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...
Spin–Spin Coupling: One-Bond Coupling
Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.

