arXiv subjects

Aleksandr Rodin

Publications and source records attributed to Aleksandr Rodin.

25 records · Page 2Linked to original sources

arXiv2021

Phonon Casimir effect in polyatomic systems

The phonon Casimir effect describes the phonon-mediated interaction between defects in condensed-matter systems. Using the path-integral formalism, we derive a general method for calculating the Helmholtz free energy due to vibrational modes in systems of arbitrary dimensionality and composition. Our results make it possible to extract the defect interaction energy at any temperature for various defect configurations. We demonstrate our approach in action by performing numerical calculations for mono- and diatomic chains, as well as a diatomic molecule, at zero and finite temperatures and validate our results using exact diagonalization.

cond-mat.mes-hall↗

arXiv2020

Hydrogen adatoms on graphene: the role of hybridization and lattice distortion

Hydrogen adatoms on graphene are investigated using DFT and analytical approaches. We demonstrate that the level of lattice deformation due to the hydrogen adsorption does not substantially change the coupling between the graphene $p_{z}$ orbitals. The hybridization primarily takes place between the adsorbate's s orbital and the graphene $p_{z}$ orbitals. We also show that the impurity interaction with the graphene atoms is limited to only a few nearest neighbors, allowing us to construct a compact TB model for the impurity-graphene system with an arbitrary impurity distribution. The complexity of our model scales with the number of impurities, not their separation, making it especially useful in the study of low impurity concentrations.

cond-mat.mtrl-sci↗

arXiv2019

Graphene-mediated interaction between adsorbed impurities

Interaction between adsorbed atoms in graphene is studied using a combination of DFT and the path integral formalism. Our results reveal a complex non-monotonic interaction profile. We show that the strength and sign of the interaction are dictated by the arrangement of impurities, as well as the system doping. These findings can be used to interpret the complex behavior of impurities in experimentally realized systems, as well as other classes of impurities, such as C substitutions in graphene.

cond-mat.mes-hall↗

arXiv2019

Many-impurity phonon Casimir effect in atomic chains

Phonon Casimir effect is the long-range interaction between impurities in condensed matter systems, mediated by vacuum fluctuations of the phonon field. For pairs of impurities, this interaction has been shown to follow a quasi-power law at zero-temperature and evolve into an exponentially decaying form as the temperature is increased. This work introduces an approach to deal with systems of more than two impurities, both at zero and finite temperatures.

cond-mat.mes-hall↗

arXiv2019

Bulk-mediated interaction between impurities in 1D atomic chains

A combination of numerical and analytical methods is employed to study a one-dimensional chain of identical atoms with adsorbates. We show that the electron-mediated interaction energy between two impurities can change sign and magnitude depending on the adatom-adatom separation, as well as the system doping. By focusing on this simple system, we provide insight into the bulk-mediated interaction for more complex materials.

cond-mat.mes-hall↗

arXiv2018

Localized Magnetic States in 2D Semiconductors

We study the formation of magnetic states in localized impurities embedded into two-dimensional semiconductors. By considering various energy configurations, we illustrate the interplay of the gap and the bands in the system magnetization. Finally, we consider finite-temperature effects to show how increasing $T$ can lead to formation and destruction of magnetization.

cond-mat.mes-hall↗

arXiv2014

Spin-Orbit Proximity Effect in Graphene

The development of a spintronics device relies on efficient generation of spin polarized currents and their electric field controlled manipulation. While observation of exceptionally long spin relaxation lengths make graphene an intriguing material for spintronics studies, modulation of spin currents by gate field is almost impossible due to negligibly small intrinsic spin orbit coupling (SOC) of graphene. In this work, we create an artificial interface between monolayer graphene and few-layers semiconducting tungsten disulfide (WS2). We show that in such devices graphene acquires a SOC as high as 17meV, three orders of magnitude higher than its intrinsic value, without modifying any of the structural properties of the graphene. Such proximity SOC leads to the spin Hall effect even at room temperature and opens the doors for spin FETs. We show that intrinsic defects in WS2 play an important role in this proximity effect and that graphene can act as a probe to detect defects in semiconducting surfaces.

cond-mat.mes-hall↗