Similarities and trends in adsorbate induced reconstruction-Structure and stability of FCC iron and cobalt surface carbides

Thin FCC (100) iron and cobalt carbide films were prepared on Cu(1 0 0) to study the connection between their structure, electronic properties and stability. We present the first detailed, real space experimental confirmation of the C-induced clock reconstruction on the FCC(1 0 0) surfaces of iron and cobalt. Both Fe and Co surface carbides show p4g (2 x 2) surface reconstruction with tetracoordinated square planar carbon and pure FCC (100) metal layers underneath. Combining tip-sample distance dependent STM imaging with theoretical calculations we present different imaging modes of Fe2C. Using a combination of angle-resolved x-ray photoelectron spectroscopy (AR-XPS), Auger electron spectroscopy (AES), low energy electron diffraction (LEED), scanning tunneling microscopy (STM), and theoretical calculations we provide detailed electronic and structural models for Fe2C and Co2C p4g (2 x 2) surface carbides and other 2D Fe2X interstitial compound systems. In various Fe2X (X = B, C, N, O) surface compounds moving to the right in the periodic table with increasing electrons the reconstruction becomes less favorable, while iron carbide shows the highest stability.

Automated summary

The relationship between structure, electronic properties, and stability of thin FCC (100) iron and cobalt carbide films prepared on Cu(1 0 0) was studied. The first experimental confirmation of the C-induced clock reconstruction on the FCC(1 0 0) surfaces of iron and cobalt was presented. Both Fe and Co surface carbides exhibited a p4g (2 x 2) surface reconstruction with tetracoordinated square planar carbon and pure FCC (100) metal layers underneath. Detailed electronic and structural models for Fe2C and Co2C p4g (2 x 2) surface carbides and other 2D Fe2X interstitial compound systems were provided using AR-XPS, AES, LEED, STM, and theoretical calculations.