arXiv subjects

Predrag Lazic

Publications and source records attributed to Predrag Lazic.

8 recordsLinked to original sources

arXiv2020

Smartphone camera based pointer

Large screen displays are omnipresent today as a part of infrastructure for presentations and entertainment. Also powerful smartphones with integrated camera(s) are ubiquitous. However, there are not many ways in which smartphones and screens can interact besides casting the video from a smartphone. In this paper, we present a novel idea that turns a smartphone into a direct virtual pointer on the screen using the phone's camera. The idea and its implementation are simple, robust, efficient and fun to use. Besides the mathematical concepts of the idea we accompany the paper with a small javascript project (www.mobiletvgames.com) which demonstrates the possibility of the new interaction technique presented as a massive multiplayer game in the HTML5 framework.

cs.HC↗

arXiv2015

What Makes Effective Gating Possible in Two-Dimensional Heterostructures?

Electrostatic gating provides a way to obtain key functionalities in modern electronic devices and to qualitatively alter materials properties. While electrostatic description of such gating gives guidance for related doping effects, inherent quantum properties of gating provide opportunities for intriguing modification of materials and unexplored devices. Using first-principles calculations for Co/bilayer graphene, Co/BN, and Co/benzene, as well as a simple physical model, we show that magnetic heterostructures with two-dimensional layered materials can manifest tunable magnetic proximity effects. van der Waals bonding is identified as a requirement for large electronic structure changes by gating. In particular, the magnitude and sign of spin polarization in physisorbed graphene can be controlled by gating, which is important for spintronic devices.

cond-mat.mtrl-sci↗

arXiv2010

Controlling the Local Spin-Polarization at the Organic-Ferromagnetic Interface

By means of ab initio calculations and spin-polarized scanning tunneling microscopy experiments we show how to manipulate the local spin-polarization of a ferromagnetic surface by creating a complex energy dependent magnetic structure. We demonstrate this novel effect by adsorbing organic molecules containing pi(pz)-electrons onto a ferromagnetic surface, in which the hybridization of the out-of-plane pz atomic type orbitals with the d-states of the metal leads to the inversion of the spin-polarization at the organic site due to a pz - d Zener exchange type mechanism. As a key result, we demonstrate that it is possible to selectively inject spin-up and spin-down electrons from the same ferromagnetic surface, an effect which can be exploited in future spintronic devices.

cond-mat.mtrl-sci↗

arXiv2010

Spin- and energy-dependent tunneling through a single molecule with intramolecular spatial resolution

We investigate the spin- and energy dependent tunneling through a single organic molecule (CoPc) adsorbed on a ferromagnetic Fe thin film, spatially resolved by low-temperature spin-polarized scanning tunneling microscopy. Interestingly, the metal ion as well as the organic ligand show a significant spin-dependence of tunneling current flow. State-of-the-art ab initio calculations including also van-der-Waals interactions reveal a strong hybridization of molecular orbitals and surface 3d states. The molecule is anionic due to a transfer of one electron, resulting in a non-magnetic (S= 0) state. Nevertheless, tunneling through the molecule exhibits a pronounced spin-dependence due to spin-split molecule-surface hybrid states.

cond-mat.mtrl-sci↗

arXiv2004

Localization and hybridization of electronic states in thin films of Ag on V(100)

We have studied the electronic states in 1-5 layers thick Ag films on V(100), by means of ab initio density functional calculations. Due to the mismatch of the electronic structure of Ag and V, quantum well states of both sp and d character localized on Ag films are formed. We find that the hybridization of the Ag quantum well states with the V orbitals is nevertheless important, and must be taken into account in order to fully understand the observed properties, in particular the energies and the dispersion of the photoemission peaks in ARPES experiments.

cond-mat.mtrl-sci↗

arXiv2004

The Robin Hood method - a novel numerical method for electrostatic problems based on a non-local charge transfer

We introduce a novel numerical method, named the Robin Hood method, of solving electrostatic problems. The approach of the method is closest to the boundary element methods, although significant conceptual differences exist with respect to this class of methods. The method achieves equipotentiality of conducting surfaces by iterative non-local charge transfer. For each of the conducting surfaces non-local charge transfers are performed between surface elements which differ the most from the targeted equipotentiality of the surface. The method is tested against analytical solutions and its wide range of application is demonstrated. The method has appealing technical characteristics. For the problem with N surface elements, the computational complexity of the method essentially scales with N^alpha, where alpha < 2, the required computer memory scales with N, while the error of the potential decreases exponentially with the number of iterations for many orders of magnitude of the error, without the presence of the Critical Slowing Down. The Robin Hood method has a large potential of application in other classical as well as quantum problems. Some possible applications outside electrostatics are outlined.

physics.comp-ph↗

arXiv2004

The Structure of Ultrathin Ag Films on Pd(111)

We have performed ab initio density functional calculations of thin Ag films on the Pd(111) surface. We have calculated the structural properties and the electronic bands of the Ag/Pd systems. There is a band gap in the electronic density of states around the centre of the two-dimensional Brillouin zone of the Pd(111) surface, which makes possible the formation of localised states in the adsorbed silver films. We find that quantum well states may form at binding energies around 4 eV.

cond-mat.mtrl-sci↗

arXiv2001

Vitrification in a 2D Ising model with mobile bonds

A bond-disordered two-dimensional Ising model is used to simulate Kauzmann's mechanism of vitrification in liquids, by a Glauber Monte Carlo simulation. The rearrangement of configurations is achieved by allowing impurity bonds to hop to nearest neighbors at the same rate as the spins flip. For slow cooling, the theoretical minimum energy configuration is approached, characterized by an amorphous distribution of locally optimally arranged impurity bonds. Rapid cooling to low temperatures regularly finds bond configurations of higher energy, which are both a priori rare and severely restrictive to spin movement, providing a simple realization of kinetic vitrification. A supercooled liquid regime is also found, and characterized by a change in sign of the field derivative of the spin-glass susceptibility at a finite temperature.

cond-mat.stat-mech↗