Chiral Spin Texture in the Charge-Density-Wave Phase of the Correlated Metallic Pb / Si ( 111 ) Monolayer

C. Tresca (1, 2) , C. Brun (1) , T. Bilgeri (1) , G. Menard (1) , V. Cherkez (1) , R. Federicci (1) , D. Longo (1) , F. Debontridder (1) , M. D’angelo (1) , D. Roditchev (1, 3) , G. Profeta (2) , M. Calandra (1) , T. Cren (1)

1 INSP-E2 - Spectroscopie des nouveaux états quantiques
2 DSFC - Department of Physical and Chemical Sciences [L'Aquila]
3 LPEM - Laboratoire de Physique et d'Etude des Matériaux (UMR 8213)

We investigate the 1=3 monolayer α-Pb=Sið111Þ surface by scanning tunneling spectroscopy (STS) and fully relativistic first-principles calculations. We study both the high-temperature ffiffi ffi 3 p × ffiffi ffi 3 p and low-temperature 3 × 3 reconstructions and show that, in both phases, the spin-orbit interaction leads to an energy splitting as large as 25% of the valence-band bandwidth. Relativistic effects, electronic correlations, and Pb-substrate interaction cooperate to stabilize a correlated low-temperature paramagnetic phase with well-developed lower and upper Hubbard bands coexisting with 3 × 3 periodicity. By comparing the Fourier transform of STS conductance maps at the Fermi level with calculated quasiparticle interference from nonmagnetic impurities, we demonstrate the occurrence of two large hexagonal Fermi sheets with in-plane spin polarizations and opposite helicities.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

C. Tresca, C. Brun, T. Bilgeri, G. Menard, V. Cherkez, et al.. Chiral Spin Texture in the Charge-Density-Wave Phase of the Correlated Metallic Pb / Si ( 111 ) Monolayer. Physical Review Letters, 2018, 120 (19), pp.196402. ⟨10.1103/PhysRevLett.120.196402⟩. ⟨hal-01792155⟩