"Low work function in the 122-family of iron-based superconductors"

H. Pfau: H. Soifer, J. A. Sobota, A. Gauthier, C. R. Rotundu, J. C. Palmstrom, I. R. Fisher, G.-Y. Chen, H.-H. Wen, Z.-X. Shen, and P. S. Kirchmann; Physical Review Materials, 03/04/20.

Additional Authors: H. Soifer, J. A. Sobota, A. Gauthier, C. R. Rotundu, J. C. Palmstrom, I. R. Fisher, G.-Y. Chen, H.-H. Wen, Z.-X. Shen, and P. S. Kirchmann

Abstract:

We determine the work functions of the iron arsenic compounds AFe2As2 (A=Ca,Ba,Cs) using photoemission spectroscopy to be 2.7 eV for CaFe2As2, 1.8 eV for BaFe2As2, and 1.3 eV for CsFe2As2. The work functions of these 122 iron-based superconductors track those of the elementary metal A but are substantially smaller. The most likely explanation of this observation is that the cleaving surface exposes only half an A-layer. The low work function and good photoemission cross section of BaFe2As2 and CsFe2As2 enable photoemission even from a common white LED light.