Cr(001) and Fe(001) clean surfaces exhibit a dz2-like surface state at -0.06 eV and +0.17 eV below and above the Fermi level, respectively.[1] Band-structure calculations predicted that it was highly spin-polarized due to originating from minority spin bands.[1] Tunneling spectroscopy via such surface states makes us possible to investigate spin dependent electronic properties of material surfaces on atomic scale.[2] Spin-polarized scanning tunneling microscopy and spectroscopy (SP-STM/STS) revealed that the Cr(001) clean surface exhibited `topological antiferromagnetism.[3] Recently, we found that the Cr(001) thin film surfaces grown on the MgO(001) substrates with an Fe seed layer showed a c(3√2x√2)R45°-C reconstructed structure[4] and an one-dimensional surface state laterally confined by segregated impurity atoms. Furthermore, our SP-STM/STS study showed that the one-dimensional surface state was spin-polarized.
On Fe(001) surfaces with the c(3√2x√2)-C reconstruction, similar one-dimensional surface states was observed using STM/STS[5], and first-principle calculations said that they are highly spin-polarized, due to originating from a minority spin bands[6].
In this presentation, we report the origin of the one-dimensional spin-polarized surface states on the c(3√2x√2)R45°-C/Cr(001) thin film surfaces by comparing with results between experimental and first-principle calculation.
[1] J. A. Stroscio et al., PRL 75, 2960 (1995).
[2] M. Bode, Rep. Prog. Phys. 66, 523 (2003).
[3] M. Kleiber et al., PRL 85, 4606 (2000).
[4] H. Oka and K. Sueoka, submitted.
[5] G. Panaccione et al., PRB 73, 35431 (2006).
[6] G. Trimarchi and N. Binggeli, PRB 72, 81408(R) (2005). |