Iron-based superconductors (FeSC) are iron-containing chemical compounds whose superconducting properties were discovered in 2006[[Hosono2006]] 

## Classes/composition
### Pnictides (FeAs, ...)
contain chemical elements in group 15 of the periodic table, here typically arsenic (As) and phosphorus (P)

### Oxypnictides (LaOFeAs, ...) often referred to as the '1111' pnictides.

###  Chalcogenides (FeSe, ...)

## Structure
* Layered
* Most of the correlated physics (superconductivity, magnetism) occurs in the Fe(Pn or Ch) layers
* Fe atoms form approximately square lattice


## Phase diagram
* Parent (undoped compound) is typically a spin density wave, sometimes nematic at low temperature
* superconductivity has transition temperatures up to mid 50K
* Phases can be tuned by composition, pressure, strain, and in the case of thin films by substrate (strain, electron phonon coupling)
* superconductivity exists both for electron and hole doping
	* for review see https://arxiv.org/pdf/1604.03566.pdf

## Electronic properties
* Can have one or more types of Fermi surfaces 
* Fe atoms carry local magnetic moments in the magnetic (SDW) phases
* Electronic correlations are believed to be weaker than in the case of cuprates [[Basov]] -- band and mean-field theory may work better