Electronic and magnetic structure of the Cr$(001)$ surface.

Cyrille Barreteau (1) , Parwana Habibi (1) , Alexander Smogunov (1)

1 SPCSI - Service de Physique et de Chimie des Surfaces et Interfaces

Combined Density Functional Theory (DFT) and Tight-Binding (TB) calculations are carried out to study the electronic and magnetic structure of the $(001)$ surface of Chromium. Our aim is to identify and characterize the most prominent electronic surface states and make the connection with the main experimental results. We show that a low dispersive minority spin surface state at the center of the Surface Brillouin zone plays a crucial role. This surface states of $\Delta_1$ symmetry at 0.58eV above the Fermi level exhibits predominantly a $d_{z^2}$ as well as $p_z$ orbital character. Local density of states (LDOS) analysis in the vacuum above the surface shows that the sharp feature originating from this surface state persists far away above the surface because of the slow decay rate of $p_z$ wave functions. Finally by artificially lowering the surface magnetic moment $m_S$ on the outermost surface layer we find an excellent agreement with experiments for $m_S=1.75\mu_B$. In addition we propose that some extra Spin Polarized Scanning Tunneling Spectroscopy (SP-STS) experiments should be made at smaller tip-surface distances to reveal additional features originating from majority spin $d_{z^2}$ surface states.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Cyrille Barreteau, Parwana Habibi, Alexander Smogunov. Electronic and magnetic structure of the Cr$(001)$ surface.. Journal of Physics: Condensed Matter, 2013, 25 (14), pp.146002. ⟨10.1088/0953-8984/25/14/146002⟩. ⟨hal-00864638⟩