Lattice Dynamics of Bi2Те3 and Vibrational Modes in Raman Scattering of Topological Insulators MnBi2Te4·n(Bi2Te3)

JETP Letters - This work is devoted to the experimental study and symmetry analysis of the Raman-active vibration modes in MnBi2Te4·n(Bi2Te3) van der Waals topological insulators, where n is...     

Natural sulfur-containing minerals as topological insulators with a wide band gap

The electronic structure of quaternary natural minerals PbBi₂Te₂S₂ (aleksite), Pb₂Bi₂Te₂S₃ (saddlebackite), and PbBi₄Te₄S₃ (C phase) has been theoretically studied. These compounds have a layered structure: aleksite and saddlebackite are formed by seven- and nine-layer blocks, respectively, and C phase consists of five- and seven-layer blocks separated by van der Waals gaps. It has been shown that all studied materials are three-dimensional topological insulators with a wide band gap in the electronic spectrum and have a high spin polarization. For these reasons, they are promising for applications.     

Impact of Co Atoms on the Electronic Structure of Bi2Te3 and MnBi2Te4 Topological Insulators

Journal of Experimental and Theoretical Physics - This work is devoted to an experimental investigation of the electronic structure of the surface of topological insulators of various stoichiometry...     

Magnetic ordering in digital alloys of group-IV semiconductors with 3<Emphasis Type="Italic">d</Emphasis>-transition metals

The ab initio investigation of the magnetic ordering in digital alloys consisting of monolayers of 3d-transition metals Ti, V, Cr, Mn, Fe, Co, and Ni introduced into the Si, Ge, and Si_0.5Ge_0.5 semiconductor hosts is reported. The calculations of the parameters of the exchange interactions and total-energy calculations indicate that the ferromagnetic order appears only in the manganese monolayers, whereas the antiferromagnetic order is more probable in V, Cr, and Fe monolayers, and Ti, Co, and Ni monolayers are nonmagnetic. The stability of the ferromagnetic phase in digital alloys containing manganese monolayers has been analyzed using the calculations of magnon spectra.     

Efficient step-mediated intercalation of silver atoms deposited on the Bi2Se3 surface

The intercalation of silver atoms into the van der Waals gap of the prototypical three-dimensional topological insulator Bi₂Se₃ is studied by means of ab initio total-energy calculations. Two possible intercalation mechanisms are examined: penetration from the terrace under the step and penetration via interstitials and/or vacancies of the surface quintuple layer block. It is shown that the former mechanism is strongly preferred over the latter one due to significant energy gain appearing at the step. According to performed estimations, the room temperature diffusion length of silver atoms reaches ten microns within a couple of minutes both on the surface and within the van der Waals gap, which essentially exceeds a typical distance between steps. These results shed light on the mechanism of intercalation of metal atoms deposited on the Bi₂Se₃ surface.     

Digital magnetic heterostructures based on Si and Fe

This paper reports on the results of ab initio calculations of the electronic and magnetic properties of Si digital heterostructures doped with a Fe monolayer of the substitutional or interstitial type. It has been revealed that, after the structural relaxation, heterostructures of both types exhibit a two-dimensional metallic behavior and a ferromagnetic ordering in the range of Si spacer thicknesses up to 19 atomic layers. The magnetization and spin polarization at the Fermi level for the heterostructures with an Fe monolayer of the substitutional type are two times higher than those for the system with an Fe monolayer of the interstitial type.     

Magnetic extension as an efficient method for realizing the quantum anomalous hall state in topological insulators

A new efficient method is proposed for inducing magnetism on the surface of a topological insulator through the deposition of a thin film of an isostructural magnetic insulator whose atomic composition is maximally close to that of the topological material. Such a design prevents the formation of a strong interface potential between subsystems. As a result, the topological state freely penetrates into the magnetic region, where it interacts with the exchange field and gets significantly split at the Dirac point. It is shown that the application of this approach to thin films of a tetradymite-like topological insulator allows realizing the quantum anomalous Hall state with a band gap of several tens of meV.     

Erratum to: Several Articles in JETP Letters

JETP Letters - An Erratum to this paper has been published: https://doi.org/10.1134/S0021364022380015