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; P. S. Kirchmann

doi:10.1103/PhysRevMaterials.4.034801

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, P. S. Kirchmann

DOI 10.1103/PhysRevMaterials.4.034801 · Physical Review Materials

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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.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
CaFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
BaFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
CsFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown