The Tl/Si(111)1 × 1 surface is a representative of a 2D layer with Rashba-type spin-split electronic bands. To utilize the spin polarization, doping of the system should be understood on atomic level. We present a study of two types of atomic defects predicted to dope the considered electronic system - Si-induced vacancies and defects associated with the presence of extra Tl atoms. Structural calculations based on density functional theory (DFT) confirm the stability of the proposed defect structure consisting of an extra Si atom and missing seven Tl atoms as proposed in an earlier experimental study. The calculated spatial charge distributions indicate an enhancement of the charge around the extra Si atom, which correctly reproduces topographies of the corresponding scanning tunneling microscopy images while the calculated local densities of states of this system explain obtained scanning tunneling spectra. The DFT structural calculations let us determine the atomic structure of the defect caused by the presence of an extra Tl atom. The calculated spatial charge distributions show a ring-like feature around the extra Tl atom. The obtained results indicate a charge transfer from the central extra Tl atom to its vicinity in the agreement with earlier photoemission measurements.

Charles University Faculty of Mathematics and Physics Department of Surface and Plasma Science 5 Holešovičkách 2 180 00 Prague Czech Republic

Instytut Fizyki Doswiadczalnej Universytet Wroclawski pl Maksa Borna 9 50 204 Wroclaw Poland

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Kim KS, Jung SC, Kang MH, Yeom HW. Nearly massless electrons in the silicon interface with a metal film. Phys. Rev. Lett. 2010;104:246803. doi: 10.1103/PhysRevLett.104.246803. PubMed DOI

Zhang T, et al. Superconductivity in one-atomic-layer metal films grown on Si(111) Nature Phys. 2010;6:104–108. doi: 10.1038/nphys1499. DOI

Sakamoto K, et al. Abrupt rotation of the rashba spin to the direction perpendicular to the surface. Phys. Rev. Lett. 2009;102:096805. doi: 10.1103/PhysRevLett.102.096805. PubMed DOI

Ibañez Azpiroz J, Eiguren A, Bergara A. Relativistic effects and fully spin-polarized Fermi surface at the Tl/Si(111) surface. Phys. Rev. B. 2011;84:125435. doi: 10.1103/PhysRevB.84.125435. DOI

Stolwijk SD, Schmidt AB, Donath M, Sakamoto K, Krüger P. Rotating spin and giant splitting: Unoccupied surface electronic structure of tl/si(111) Phys. Rev. Lett. 2013;111:176402. doi: 10.1103/PhysRevLett.111.176402. PubMed DOI

Sakamoto K, et al. Valley spin polarization by using the extraordinary Rashba effect on silicon. Nat. Commun. 2013;4:2073. doi: 10.1038/ncomms3073. PubMed DOI

Sakamoto K, et al. Symmetry induced peculiar Rashba effect on thallium adsorbed Si(111) surfaces. J. of Electron Spectrosc. Relat. Phenom. 2015;201:88–91. doi: 10.1016/j.elspec.2014.09.008. DOI

Stolwijk SD, Sakamoto K, Schmidt AB, Krüger P, Donath M. Thin line of a rashba-type spin texture: Unoccupied surface resonance of tl/si(111) along ΓM. Phys. Rev. B. 2014;90:161109. doi: 10.1103/PhysRevB.90.161109. DOI

Stolwijk S, Sakamoto K, Schmidt A, Krüger P, Donath M. Spin texture with a twist in momentum space for Tl/Si(111) Phys. Rev. B. 2015;91:245420. doi: 10.1103/PhysRevB.91.245420. DOI

Stolwijk SD, Schmidt AB, Sakamoto K, Krüger P, Donath M. Valley spin polarization of Tl/Si(111) Phys. Rev. Materials. 2017;1:064604. doi: 10.1103/PhysRevMaterials.1.064604. DOI

Gierz I, et al. Silicon surface with giant spin splitting. Phys. Rev. Lett. 2009;103:046803. doi: 10.1103/PhysRevLett.103.046803. PubMed DOI

Sakamoto K, et al. Peculiar rashba splitting originating from the two-dimensional symmetry of the surface. Phys. Rev. Lett. 2009;103:156801. doi: 10.1103/PhysRevLett.103.156801. PubMed DOI

Höpfner P, et al. Three-dimensional spin rotations at the fermi surface of a strongly spin-orbit coupled surface system. Phys. Rev. Lett. 2012;108:186801. doi: 10.1103/PhysRevLett.108.186801. PubMed DOI

Yaji K, et al. Large Rashba spin splitting of a metallic surface-state band on a semiconductor surface. Nat. Commun. 2010;1:17. doi: 10.1038/ncomms1016. PubMed DOI PMC

Rashba EI. Properties of semiconductors with an extremum loop .1. cyclotron and combinational resonance in a magnetic field perpendicular to the plane of the loop. Soviet Phys.-Solid State. 1960;2:1109–1122.

Bychkov Y, Rashba E. Properties of a 2D electron gas with lifted spectral degeneracy. Jetp. Lett. 1984;39:78.

Gruznev DV, et al. A strategy to create spin-split metallic bands on silicon using a dense alloy layer. Scientific Reports. 2014;4:4742. doi: 10.1038/srep04742. PubMed DOI PMC

Matetskiy AV, et al. Two-dimensional superconductor with a giant rashba effect: One-atom-layer Tl-Pb compound on si(111) Phys. Rev. Lett. 2015;115:147003. doi: 10.1103/PhysRevLett.115.147003. PubMed DOI

Gruznev DV, et al. Electronic band structure of a Tl/Sn atomic sandwich on Si (111) Phys. Rev. B. 2015;91:035421. doi: 10.1103/PhysRevB.91.035421. DOI

Lin Y-M, et al. Wafer-scale graphene integrated circuit. Science. 2011;332:1294–1297. doi: 10.1126/science.1204428. PubMed DOI

Telychko M, et al. Electronic and chemical properties of donor, acceptor centers in graphene. ACS Nano. 2015;9:9180–9187. doi: 10.1021/acsnano.5b03690. PubMed DOI

Morikawa, H., Hwang, C. C. & Yeom, H. W. Controlled electron doping into metallic atomic wires: Si (111) 4 × 1 -In. Phys. Rev. B81 (2010).

Ming, F. et al. Realization of a hole-doped Mott insulator on a triangular silicon lattice. Phys. Rev. Lett. 119 (2017). PubMed

Lee SS, et al. Structural and electronic properties of thallium overlayers on the Si(111)-7 × 7 surface. Phys. Rev. B. 2002;66:233312. doi: 10.1103/PhysRevB.66.233312. DOI

Noda T, Mizuno S, Chung JW, Tochihara H. T4 site adsorption of Tl atoms in a Si(111)-(1 × 1)-Tl structure, determined by low-energy electron diffraction analysis. Jpn. J. Appl. Phys. 2003;42:L319. doi: 10.1143/JJAP.42.L319. DOI

Kim ND, et al. Structural properties of a thallium-induced si(111)-1 × 1 surface. Phys. Rev. B. 2004;69:195311. doi: 10.1103/PhysRevB.69.195311. DOI

Vitali L, Leisenberger FP, Ramsey MG, Netzer FP. Thallium overlayers on Si(111): Structures of a “new” group III element. J. Vac. Sci. Technol. A. 1999;17:1676. doi: 10.1116/1.581871. DOI

Vitali L, Ramsey MG, Netzer FP. Rotational epitaxy of a “soft” metal overlayer on Si(111) Surf. Sci. 2000;452:L281. doi: 10.1016/S0039-6028(00)00367-8. DOI

Ichinokura S, et al. Superconductivity in thallium double atomic layer and transition into an insulating phase intermediated by a quantum metal state. 2D Mater. 2017;4:025020. doi: 10.1088/2053-1583/aa57f9. DOI

Mihalyuk AN, et al. Double-atomic layer of Tl on Si(111): Atomic arrangement and electronic properties. Surf. Sci. 2018;668:17–22. doi: 10.1016/j.susc.2017.10.010. DOI

Kocán P, Sobotk P, Ošt'ádal I. Metallic-like thallium overlayer on a Si(111) surface. Phys. Rev. B. 2011;84:233304. doi: 10.1103/PhysRevB.84.233304. DOI

Matvija P, Rozbořil F, Sobotk P, Ošt’ádal I, Kocán P. Pair correlation function of a 2D molecular gas directly visualized by scanning tunneling microscopy. J. Phys. Chem. Lett. 2017;8:4268–4272. doi: 10.1021/acs.jpclett.7b01965. PubMed DOI

Matvija P, et al. Electric-field-controlled phase transition in a 2D molecular layer. Scientific Reports. 2017;7:7357. doi: 10.1038/s41598-017-07277-7. PubMed DOI PMC

Kocán P, Sobotk P, Matvija P, Setvn M, Ošt'ádal I. An STM study of desorption-induced thallium structures on the Si(111) surface. Surf. Sci. 2012;606:991–995. doi: 10.1016/j.susc.2011.12.016. DOI

Kocán P, Sobotk P, Ošt'ádal I. Desorption-induced structural changes of metal/Si(111) surfaces: Kinetic Monte Carlo simulations. Phys. Rev. E. 2013;88:022403. doi: 10.1103/PhysRevE.88.022403. PubMed DOI

Rutter GM, et al. Scattering and interference in epitaxial graphene. Science. 2007;317:219–222. doi: 10.1126/science.1142882. PubMed DOI

Kresse G, Hafner J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B. 1993;47:558–561. doi: 10.1103/PhysRevB.47.558. PubMed DOI

Kresse G, Hafner J. Ab initio molecular-dynamics simulation of the liquid-metal-amorphous-semiconductor transition in germanium. Phys. Rev. B. 1994;49:14251–14269. doi: 10.1103/PhysRevB.49.14251. PubMed DOI

Kresse G, Furthmüller J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comp. Mat. Sci. 1996;6:15–50. doi: 10.1016/0927-0256(96)00008-0. PubMed DOI

Kresse G, Furthmüller J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B. 1996;54:11169–11186. doi: 10.1103/PhysRevB.54.11169. PubMed DOI

Blöchl PE. Projector augmented-wave method. Phys. Rev. B. 1994;50:17953–17979. doi: 10.1103/PhysRevB.50.17953. PubMed DOI

Kresse G, Joubert D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B. 1999;59:1758–1775. doi: 10.1103/PhysRevB.59.1758. DOI

Perdew JP, Burke K, Ernzerhof M. Generalized gradient approximation made simple. Phys. Rev. Lett. 1996;77:3865–3868. doi: 10.1103/PhysRevLett.77.3865. PubMed DOI

Setvín M, et al. Ultrasharp tungsten tips—characterization and nondestructive cleaning. Ultramicroscopy. 2012;113:152–157. doi: 10.1016/j.ultramic.2011.10.005. DOI

Prietsch M, Samsavar A, Ludeke R. Structural and electronic properties of the Bi/GaP(110) interface. Phys. Rev. B. 1991;43:11850. doi: 10.1103/PhysRevB.43.11850. PubMed DOI