We present ultrahigh resolution angle-resolved photoemission data of the prototypical Kondo lattice system YbRh 2Si 2, using a 7 eV laser photon source. Detailed temperature dependent measurements reveal the development of coherent states, in the form of sharp, weakly dispersing peaks at the lowest energy of single-electron spectra, below a characteristic temperature. The characteristic temperature, obtained from angle-resolved photoemission, is intriguingly of exactly the same scale as the ener…
Read moreWe present ultrahigh resolution angle-resolved photoemission data of the prototypical Kondo lattice system YbRh 2Si 2, using a 7 eV laser photon source. Detailed temperature dependent measurements reveal the development of coherent states, in the form of sharp, weakly dispersing peaks at the lowest energy of single-electron spectra, below a characteristic temperature. The characteristic temperature, obtained from angle-resolved photoemission, is intriguingly of exactly the same scale as the energy and the lifetime of the coherent state. © 2012 American Physical Society.