uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 241) Show all publications
Ayatollahi, A., Roknabadi, M. R., Behdani, M., Shahtahmassebi, N. & Sanyal, B. (2020). Density functional investigations on the adsorption characteristics of nucleobases on germanene nanoribbons. Physica. E, Low-Dimensional systems and nanostructures, 117, Article ID 113772.
Open this publication in new window or tab >>Density functional investigations on the adsorption characteristics of nucleobases on germanene nanoribbons
Show others...
2020 (English)In: Physica. E, Low-Dimensional systems and nanostructures, ISSN 1386-9477, E-ISSN 1873-1759, Vol. 117, article id 113772Article in journal (Refereed) Published
Abstract [en]

In order to explore the possibility of using 2D nanostructures as biosensors, we have studied the adsorption characteristics of nucleotide bases on armchair germanene nanoribbon (AGeNR) using density functional theory with several approximations of exchange-correlation functionals with the addition of dispersion correction. It has been found that the dispersion interactions have the key role in characterizing adsorption phenomena through the non-covalent interactions. The structural and electronic properties of the nucleobase-nanoribbon complexes have been investigated along with the study of the dependence of binding energies on ribbon widths and hence the edge (armchair or zigzag) effects. A physisorption process with binding energies in the range of about 0.83-1.37 eV has been found for 10-AGeNR, which alters the electronic and structural properties of the subsystems indicating the potential use of these complexes as biosensors.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Adsorption, Nucleobases, Germanene nanoribbon, Dispersion-corrected density functional theory
National Category
Other Physics Topics
Identifiers
urn:nbn:se:uu:diva-402377 (URN)10.1016/j.physe.2019.113772 (DOI)000504664500012 ()
Funder
Swedish Research Council, 2016-05366Swedish Research Council, 2017-05447
Available from: 2020-01-29 Created: 2020-01-29 Last updated: 2020-01-29Bibliographically approved
Li, H., Duan, T., Haldar, S., Sanyal, B., Eriksson, O., Jafri, H., . . . Leifer, K. (2020). Direct Writing of Lateral Fluorographene Nanopatterns with Tunable Bandgaps and Its Application in New Generation of Moiré Superlattice. Applied Physics Reviews, 7, Article ID 011403.
Open this publication in new window or tab >>Direct Writing of Lateral Fluorographene Nanopatterns with Tunable Bandgaps and Its Application in New Generation of Moiré Superlattice
Show others...
2020 (English)In: Applied Physics Reviews, ISSN 1931-9401, Vol. 7, article id 011403Article in journal (Refereed) Published
Abstract [en]

One of the primary goals for monolayer device fabrications and an ideal model of graphene as an atomic thin “canvas” is one that permits semiconducting/insulating lateral nanopatterns to be freely and directly drawn on the semimetallic graphene surface. This work demonstrates a reversible electron-beam-activated technique that allows direct writing of semiconducting/insulating fluorographene lateral nanopatterns with tunable bandgaps on the graphene surface with a resolution down to 9–15 nm. This approach overcomes the conventional limit of semiconducting C4F in the single-sided fluorination of supported graphene and achieves insulating C2F. Moreover, applying this technique on bilayer graphene demonstrates for the first time a new type of rectangular moiré pattern arising from the generated C2F boat/graphene superlattice. This novel technique constitutes a new approach to fabricating graphene-based flexible and transparent electronic nanodevices with the CxF channels utilized as semiconducting or insulating counterparts, and also opens a route toward the tailoring and engineering of electronic properties of such materials in addition to the dominating triangular moiré patterns from a graphene/hBN system.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-401434 (URN)10.1063/1.5129948 (DOI)000515505800001 ()
Funder
Swedish Research Council, 621-2012-3679Swedish Research Council, 2016-05259Knut and Alice Wallenberg FoundationSwedish Research Council Formas, 2019-01538Swedish National Infrastructure for Computing (SNIC)
Available from: 2020-01-08 Created: 2020-01-08 Last updated: 2020-04-01Bibliographically approved
Watts, M. J., Fiducia, T. A. M., Sanyal, B., Smith, R., Walls, J. M. & Goddard, P. (2020). Enhancement of photovoltaic efficiency in CdSexTe1-x (where 0 <= x <= 1): insights from density functional theory. Journal of Physics: Condensed Matter, 32(12), Article ID 125702.
Open this publication in new window or tab >>Enhancement of photovoltaic efficiency in CdSexTe1-x (where 0 <= x <= 1): insights from density functional theory
Show others...
2020 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 32, no 12, article id 125702Article in journal (Refereed) Published
Abstract [en]

Recent advancements in CdTe photovoltaic efficiency have come from selenium grading, which reduces the band gap and significantly improves carrier lifetimes. In this work, density functional theory calculations were performed to understand the structural and electronic effects of Se alloying. Special quasirandom structures were used to simulate a random distribution of Se anions. Lattice parameters decrease linearly as Se concentration increases in line with Vegard's Law. The simulated band gap bowing shows strong agreement with experimental values. Selenium, by itself, does not introduce any defect states in the band gap and no significant changes to band structure around the Gamma point are found. Band offset values suggest a reduction of recombination across the CdSeTe/MgZnO interface at x <= 0.1875, which corresponds with the Se concentration used experimentally. Band structure analysis of two cases x = 0.03125 and x = 0.4375, shows a change from dominant Cd/Te contributions in the conduction band minimum to Cd/Se contributions as Se concentration is increased, hinting at a change in optical transition characteristics. Further calculations of optical absorption spectra suggest a reduced transition probability particularly at higher energies, which confirms experimental predictions that Se passivates the non-radiative recombination centres.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2020
Keywords
photovoltaics, density functional theory (DFT), electronic structure, CdTe, thin film, PV, CdSeTe
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-404714 (URN)10.1088/1361-648X/ab5bba (DOI)000508362800002 ()31770733 (PubMedID)
Funder
Swedish Research Council, 2017-05447
Available from: 2020-02-26 Created: 2020-02-26 Last updated: 2020-02-26Bibliographically approved
Chen, X., Liu, Y. & Sanyal, B. (2020). Manipulation of Electronic and Magnetic Properties of 3d Transition Metal (Cr, Mn, Fe) Hexamers on Graphene with Vacancy Defects: Insights from First-Principles Theory. The Journal of Physical Chemistry C, 124(7), 4270-4278
Open this publication in new window or tab >>Manipulation of Electronic and Magnetic Properties of 3d Transition Metal (Cr, Mn, Fe) Hexamers on Graphene with Vacancy Defects: Insights from First-Principles Theory
2020 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 124, no 7, p. 4270-4278Article in journal (Refereed) Published
Abstract [en]

One of the possible ways to introduce magnetism in graphene is to trap highly mobile transition metal atoms at defect sites in graphene. In this paper, based on Born-Oppenheimer molecular dynamics simulations, we investigated the self-assembly of transition metal hexamers X-6 (X = Cr, Mn, and Fe) on graphene with mono/divacancy defects and studied the fundamental electronic and magnetic properties of the resulting X-6 clusters on graphene. Interestingly, the ground state Cr-6 and Fe-6 hexamers on divacancy defects in graphene show quite small energy differences between in-plane and out-of-plane magnetism. By applying external electric fields, the easy axis of magnetization can be switched between in-plane and out-of-plane, which demonstrates potential applications in electric field-assisted magnetic recording and quantum computing.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2020
National Category
Condensed Matter Physics Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-407517 (URN)10.1021/acs.jpcc.9b07804 (DOI)000515216500038 ()
Funder
Swedish Research Council, 2016-05366Swedish Research Council, 2017-05447
Available from: 2020-03-25 Created: 2020-03-25 Last updated: 2020-03-25Bibliographically approved
Ivanov, S., Beran, P., Bush, A. A., Sarkar, T., Shafeie, S., Wang, D., . . . Mathieu, R. (2019). Cation ordering, ferrimagnetism and ferroelectric relaxor behavior in Pb(Fe1-xScx)(2/3)W1/3O3 solid solutions. European Physical Journal B: Condensed Matter Physics, 92(8), Article ID 163.
Open this publication in new window or tab >>Cation ordering, ferrimagnetism and ferroelectric relaxor behavior in Pb(Fe1-xScx)(2/3)W1/3O3 solid solutions
Show others...
2019 (English)In: European Physical Journal B: Condensed Matter Physics, ISSN 1434-6028, E-ISSN 1434-6036, Vol. 92, no 8, article id 163Article in journal (Refereed) Published
Abstract [en]

Ceramic samples of the multiferroic perovskite Pb(Fe1-xScx)(2/3)W1/3O3 with 0 <= x <= 0.4 have been synthesized using a conventional solid-state reaction method, and investigated experimentally and theoretically using first-principle calculations. Rietveld analyses of joint synchrotron X-ray and neutron diffraction patterns show the formation of a pure crystalline phase with cubic (Fm3(_)m) structure with partial ordering in the B-sites. The replacement of Fe by Sc leads to the increase of the cation order between the B and B '' sites. As the non-magnetic Sc3+ ions replace the magnetic Fe3+ cations, the antiferromagnetic state of PbFe2/3W1/3O3 is turned into a ferrimagnetic state reflecting the different magnitude of the magnetic moments on the B ' and B '' sites. The materials remain ferroelectric relaxors with increasing Sc content. Results from experiments on annealed and quenched samples show that the cooling rate after high temperature annealing controls the degree of cationic order in Pb(Fe1-xScx)(2/3)W1/3O3 and possibly also in the undoped PbFe2/3W1/3O3.

Place, publisher, year, edition, pages
SPRINGER, 2019
Keywords
Solid State and Materials
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-392576 (URN)10.1140/epjb/e2019-100149-9 (DOI)000477626500002 ()
Funder
Swedish Research Council
Available from: 2019-09-09 Created: 2019-09-09 Last updated: 2019-09-09Bibliographically approved
Rahmani, N., Ghazi, M. E., Izadifard, M., Wang, D., Shabani, A. & Sanyal, B. (2019). Density functional study of structural, electronic and magnetic properties of new half-metallic ferromagnetic double perovskite Sr2MnVO6. Journal of Physics: Condensed Matter, 31(47), Article ID 475501.
Open this publication in new window or tab >>Density functional study of structural, electronic and magnetic properties of new half-metallic ferromagnetic double perovskite Sr2MnVO6
Show others...
2019 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 31, no 47, article id 475501Article in journal (Refereed) Published
Abstract [en]

In this paper, a new half-metallic (HM) double perovskite compound is predicted with the simultaneous presence of ferromagnetism and polar distortion. The structural, electronic and magnetic properties of Sr2MnVO6 (SMVO) are calculated by density functional theory (DFT) with both generalized gradient approximation (GGA) and GGA + U approaches, where U is the on-site Coulomb interaction parameter. Different orderings of B (B') cationic sites in A(2)BB'O-6 double perovskite structure are evaluated, including rocksalt, columnar and layered arrangements for cubic, monoclinic and tetragonal crystal structures. It is found that the most stable ordering is obtained when B and B' are placed in a layered type ordering for a tetragonal crystal structure with I4/m space group, which is confirmed by phonon calculations. The B-site ordering of the Mn3+ and V5+ ions in a layered configuration leads to ferromagnetically coupled magnetic moments of 4.17 mu(B) at Mn site and 0.23 mu(B) at V site. Finally, SMVO is found to be a half-metallic ferromagnetic (HM-FM) compound with a band gap of 0.65 eV in a spin down channel with off-centered displacement of V atoms in the octahedral cage (second order Jahn-Teller effect) which can cause ferroelectricity. Therefore, SMVO is predicted to be a polar HM material and a promising candidate for multiferroic property with potential application in spintronics.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2019
Keywords
double perovskite Sr2MnVO6, multiferroics, half-metallic, density functional theory
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-393714 (URN)10.1088/1361-648X/ab35f7 (DOI)000482531700001 ()31349237 (PubMedID)
Funder
Swedish Research Council, 2016-05366Swedish Research Council, 2017-05447
Available from: 2019-09-30 Created: 2019-09-30 Last updated: 2019-09-30Bibliographically approved
Akansel, S., Kumar, A., Venugopal, V. A., Esteban-Puyuelo, R., Banerjee, R., Autieri, C., . . . Svedlindh, P. (2019). Enhanced Gilbert damping in Re-doped FeCo films: Combined experimental and theoretical study. Physical Review B, 99(17), Article ID 174408.
Open this publication in new window or tab >>Enhanced Gilbert damping in Re-doped FeCo films: Combined experimental and theoretical study
Show others...
2019 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, no 17, article id 174408Article in journal (Refereed) Published
Abstract [en]

The effects of rhenium doping in the range 0-10 at.% on the static and dynamic magnetic properties of Fe65Co35 thin films have been studied experimentally as well as with first-principles electronic structure calculations focusing on the change of the saturation magnetization (M-s) and the Gilbert damping parameter (alpha). Both experimental and theoretical results show that M-s decreases with increasing Re-doping level, while at the same time alpha increases. The experimental low temperature saturation magnetic induction exhibits a 29% decrease, from 2.31 to 1.64 T, in the investigated doping concentration range, which is more than predicted by the theoretical calculations. The room temperature value of the damping parameter obtained from ferromagnetic resonance measurements, correcting for extrinsic contributions to the damping, is for the undoped sample 2.1 x 10(-3), which is close to the theoretically calculated Gilbert damping parameter. With 10 at.% Re doping, the damping parameter increases to 7.8 x 10(-3), which is in good agreement with the theoretical value of 7.3 x 10(-3). The increase in damping parameter with Re doping is explained by the increase in the density of states at the Fermi level, mostly contributed by the spin-up channel of Re. Moreover, both experimental and theoretical values for the damping parameter weakly decrease with decreasing temperature.

National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-387290 (URN)10.1103/PhysRevB.99.174408 (DOI)000467722100005 ()
Funder
Knut and Alice Wallenberg Foundation, KAW 2012.0031Swedish Research Council, 2016-05366
Available from: 2019-06-24 Created: 2019-06-24 Last updated: 2019-06-24Bibliographically approved
Brumboiu, I. E., Haldar, S., Lüder, J., Eriksson, O., Herper, H. C., Brena, B. & Sanyal, B. (2019). Ligand effects on the linear response Hubbard U: The case of transition metal phthalocyanines. Journal of Physical Chemistry A, 123(14), 3214-3222
Open this publication in new window or tab >>Ligand effects on the linear response Hubbard U: The case of transition metal phthalocyanines
Show others...
2019 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 123, no 14, p. 3214-3222Article in journal (Refereed) Published
Abstract [en]

It is established that density functional theory (DFT) + U is a better choice compared to DFT for describing the correlated electron metal center in organometallics. The value of the Hubbard U parameter may be determined from linear response, either by considering the response of the metal site alone or by additionally considering the response of other sites in the compound. We analyze here in detail the influence of ligand shells of increasing size on the U parameter calculated from the linear response for five transition metal phthalocyanines. We show that the calculated multiple-site U is larger than the single-site U by as much as 1 eV and the ligand atoms that are mainly responsible for this difference are the isoindole nitrogen atoms directly bonded to the central metal atom. This suggests that a different U value may be required for computations of chemisorbed molecules compared to physisorbed and gas-phase cases.

National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:uu:diva-300117 (URN)10.1021/acs.jpca.8b11940 (DOI)000464768100011 ()30892039 (PubMedID)
Funder
Swedish Research Council, 2014-3776Swedish Research Council, 2016-05366Swedish Research Council, 2017-05447Knut and Alice Wallenberg Foundation, KAW-2013.0020Swedish National Infrastructure for Computing (SNIC)
Available from: 2016-08-02 Created: 2016-08-02 Last updated: 2019-05-15Bibliographically approved
Wen, X., Liu, Y., Jadhav, A., Zhang, J., Borchardt, D., Shi, J., . . . Guo, J. (2019). Materials Compatibility in Rechargeable Aluminum Batteries: Chemical and Electrochemical Properties between Vanadium Pentoxide and Chloroaluminate Ionic Liquids. Chemistry of Materials, 31(18), 7238-7247
Open this publication in new window or tab >>Materials Compatibility in Rechargeable Aluminum Batteries: Chemical and Electrochemical Properties between Vanadium Pentoxide and Chloroaluminate Ionic Liquids
Show others...
2019 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 31, no 18, p. 7238-7247Article in journal (Refereed) Published
Abstract [en]

To demonstrate the importance of electrode/electrolyte stability in rechargeable aluminum (Al) batteries, we investigate the chemical compatibility between vanadium pentoxide (V2O5), a proposed positive electrode material for Al batteries, and the common chloroaluminate ionic liquid electrolytes. We reveal that V2O5 reacts with both the Lewis acidic (Al2Cl7-) and the Lewis neutral species (AlCl4-) within the electrolyte. The reaction products are identified using a combination of electrochemical analyses, Raman spectroscopy, liquid-state and solid-state nuclear magnetic resonance (NMR) spectroscopy, and density functional theory (DFT) calculations. The results establish that V2O5 chemically reacts with Al2Cl7- to form vanadium oxychloride (VOCl3) and amorphous aluminum oxide. V2O5 also chemically reacts with AlCl4- to produce dioxovanadium chloride (VO2Cl) and a new species of metavanadate anion coordinated with aluminum chloride (AlCl3VO3-). These products furthermore exhibit electrochemical redox activity between V5+ and V2+ oxidation states. Our results have significant implications when interpreting the electrochemical properties and mechanisms of rechargeable Al-V2O5 batteries.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-395841 (URN)10.1021/acs.chemmater.9b01556 (DOI)000487859200016 ()
Funder
Swedish Research Council, 2017-05447Swedish Research Council, 2016-05366Swedish National Infrastructure for Computing (SNIC), SNIC 2018/2-51
Available from: 2019-10-25 Created: 2019-10-25 Last updated: 2019-10-25Bibliographically approved
Shabani, A., Nezhad, M. K., Rahmani, N., Roknabadi, M. R., Behdani, M. & Sanyal, B. (2019). Optical Properties of Au-Doped Titanium Nitride Nanostructures: a Connection Between Density Functional Theory and Finite-Difference Time-Domain Method. Plasmonics, 14(6), 1871-1879
Open this publication in new window or tab >>Optical Properties of Au-Doped Titanium Nitride Nanostructures: a Connection Between Density Functional Theory and Finite-Difference Time-Domain Method
Show others...
2019 (English)In: Plasmonics, ISSN 1557-1955, E-ISSN 1557-1963, Vol. 14, no 6, p. 1871-1879Article in journal (Refereed) Published
Abstract [en]

In this paper, we present a computational method to investigate optical properties of materials using a combination of density functional theory (DFT) calculations and finite-difference time-domain (FDTD) method. We show our method in the framework of an example for analyzing the effect of Au doping on optical transmission behavior of TiN compounds with a given geometry. First, DFT is employed based on generalized gradient approximation (GGA) exchange-correlation potential to investigate the electronic properties as well as dielectric function of TiN with respect to different percentages of doped Au. Our results reveal a growth in the imaginary part of dielectric function for energies below 4 eV by increasing Au doping level due to compression of Ti(1-x)Aux(N) DOS into the Fermi energy. In order to clarify the impact of Au doping on the optical behavior of Ti1-xAuxN with a given geometry, the optical dielectric function calculated from DFT was used as an input data for FDTD method to simulate a perforated surface plasmon system originated from Ti1-xAuxN-dielectric configuration via Optiwave package. It is observed that an increase in the Au level decreases the transmission intensity of excited modes of the perforated surface plasmon system, which is in agreement with the observed behavior for the imaginary part of dielectric function from DFT calculations. This implies that an enhanced imaginary part of dielectric function leads to more energy dissipation and finally less transmitted wave. The proposed method enables us to simulate optical properties of a wide range of compounds with arbitrary geometries and material-specific properties.

Place, publisher, year, edition, pages
SPRINGER, 2019
Keywords
DFT calculations, FDTD method, Dielectric function, Energy dissipation, Optical transmission
National Category
Condensed Matter Physics Theoretical Chemistry
Identifiers
urn:nbn:se:uu:diva-402230 (URN)10.1007/s11468-019-00982-1 (DOI)000502243800063 ()
Available from: 2020-01-16 Created: 2020-01-16 Last updated: 2020-01-16Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3687-4223

Search in DiVA

Show all publications