Quantum oscillations and the Fermi surface in an underdoped high-Tc superconductor

Understand

Despite twenty years of research, the phase diagram of high transition- temperature superconductors remains enigmatic.

• A central issue is the origin of the differences in the physical properties of these copper oxides doped to opposite sides of the superconducting region.
• In the overdoped regime, the material behaves as a reasonably conventional metal, with a large Fermi surface.
• The underdoped regime, however, is highly anomalous and appears to have no coherent Fermi surface, but only disconnected "Fermi arcs".