In the high-transition-temperature superconductors, the pseudogap phase becomes predominant when the density of doped holes is reduced. In this phase it has been unclear which electronic symmetries (if any) are broken, what the identity of any associated order parameter might be, and which microscopic electronic degrees of freedom are active. Here, images of the intra-unit-cell states in underdoped Bi2Sr2CaCu2O8 + δ are studied, revealing electronic nematicity of the states close to the pseudogap energy.
- M. J. Lawler
- K. Fujita
- Eun-Ah Kim
