Doping is a tried and tested method to tune the properties of a range of quantum materials either by introducing defects into the system or engineering the charge carrier concentration. Here, the authors use photoemission spectroscopy to investigate the effects of surface doping of alkali metals on the Mott insulator Ca2RuO4, revealing an orbital-selective surface metal-insulator transition induced by the surface-dopant interaction.
- Masafumi Horio
- Filomena Forte
- Johan Chang
