“Effect of edge groups on the electronic transport properties of tetrapodal diazatriptycene molecule”. Berdiyorov GR, Peeters FM, Hamoudi H, Physica. E: Low-dimensional systems and nanostructures 141, 115212 (2022). http://doi.org/10.1016/J.PHYSE.2022.115212
Abstract: We conduct ballistic transport calculations to study the electronic transport properties of diazatriptycene molecule which can be self-assembled on metallic surfaces with uniform coverage and upright orientation of the functional head group. Due to its structural asymmetry, the molecule shows a clear current rectification, where the level of the rectification depends on the nature of the head group. For example, current rectification can be increased by more than a factor of 2 by anchoring the molecules to the electrode by CN functional group or introducing insulating CH2 group between the thiol end group and the adjacent phenyl ring. Our findings show the possibility of creating self-assembled monolayer of DAT molecules with controlled electronic transport properties through functionalization of the head group.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.3
Times cited: 2
DOI: 10.1016/J.PHYSE.2022.115212
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“Effect of halogenation on the electronic transport properties of aromatic and alkanethiolate molecules”. Berdiyorov GR, Peeters FM, Hamoudi H, Physica. E: Low-dimensional systems and nanostructures 144, 115428 (2022). http://doi.org/10.1016/J.PHYSE.2022.115428
Abstract: Quantum transport calculations are conducted using nonequilibrium Green's functional formalism to study the effect of halogenation on the electronic transport properties of aromatic S-(C6H5)(2)X and alkanethiolate S-(CH2)(11)X molecules (with X = H, F, Cl, Br, or I) sandwiched between gold electrodes. In terms of conductance, both molecules show the same dependence on the halogen terminal groups despite their different electronic nature. For example, fluorination results in a reduction of the current by almost an order of magnitude, whereas iodine substitution leads to larger current as compared to the reference system (i.e. hydrogen termination). Regarding the asymmetry in the current-voltage characteristics, halogenation reduces the rectification level for the aromatic molecule with the smallest asymmetry for iodine termination. However, in the case of alkanethiolate molecule, halogen substitution increases the current rectification except for fluorination. A physical explanation of these results is obtained from the analysis of the behavior of the density of states, transmission spectra and transmission eigenstates. These findings are of practical importance in exploring the potential of halogenation for creating functional molecular self-assemblies on metallic substrates.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.3
Times cited: 1
DOI: 10.1016/J.PHYSE.2022.115428
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“Effect of ordered array of magnetic dots on the dynamics of Josephson vortices in stacked SNS Josephson junctions under DC and AC current”. Berdiyorov GR, Savel'ev S, Kusmartsev FV, Peeters FM, European physical journal : B : condensed matter and complex systems 88, 286 (2015). http://doi.org/10.1140/epjb/e2015-60628-9
Abstract: We use the anisotropic time-dependent Ginzburg-Landau theory to investigate the effect of a square array of out-of-plane magnetic dots on the dynamics of Josephson vortices (fluxons) in artificial stacks of superconducting-normal-superconducting (SNS) Josephson junctions in the presence of external DC and AC currents. Periodic pinning due to the magnetic dots distorts the triangular lattice of fluxons and results in the appearance of commensurability features in the current-voltage characteristics of the system. For the larger values of the magnetization, additional peaks appear in the voltage-time characteristics of the system due to the creation and annihilation of vortex-antivortex pairs. Peculiar changes in the response of the system to the applied current is found resulting in a “superradiant” vortex-flow state at large current values, where a rectangular lattice of moving vortices is formed. Synchronizing the motion of fluxons by adding a small ac component to the biasing dc current is realized. However, we found that synchronization becomes difficult for large magnetization of the dots due to the formation of vortex-antivortex pairs.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.461
Times cited: 1
DOI: 10.1140/epjb/e2015-60628-9
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“In-phase motion of Josephson vortices in stacked SNS Josephson junctions : effect of ordered pinning”. Berdiyorov GR, Savel'ev SE, Kusmartsev FV, Peeters FM, Superconductor science and technology 26, 125010 (2013). http://doi.org/10.1088/0953-2048/26/12/125010
Abstract: The dynamics of Josephson vortices (fluxons) in artificial stacks of superconducting-normal-superconducting Josephson junctions is investigated using the anisotropic time-dependent Ginzburg-Landau theory in the presence of a square/rectangular array of pinning centers (holes). For small values of the applied drive, fluxons in different junctions move out of phase, forming a periodic triangular lattice. A rectangular lattice of moving fluxons is observed at larger currents, which is in agreement with previous theoretical predictions (Koshelev and Aranson 2000 Phys. Rev. Lett. 85 3938). This 'superradiant' flux-flow state is found to be stable in a wide region of applied current. The stability range of this ordered state is considerably larger than the one obtained for the pinning-free sample. Clear commensurability features are observed in the current-voltage characteristics of the system with pronounced peaks in the critical current at (fractional) matching fields. The effect of density and strength of the pinning centers on the stability of the rectangular fluxon lattice is discussed. Predicted synchronized motion of fluxons in the presence of ordered pinning can be detected experimentally using the rf response of the system, where enhancement of the Shapiro-like steps is expected due to the synchronization.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.878
Times cited: 5
DOI: 10.1088/0953-2048/26/12/125010
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“Synchronized dynamics of Josephson vortices in artificial stacks of SNS Josephson junctions under both dc and ac bias currents”. Berdiyorov GR, Savel'ev SE, Milošević, MV, Kusmartsev FV, Peeters FM, Physical review : B : condensed matter and materials physics 87, 184510 (2013). http://doi.org/10.1103/PhysRevB.87.184510
Abstract: Nonlinear dynamics of Josephson vortices (fluxons) in artificial stacks of superconducting-normal-superconducting Josephson junctions under simultaneously applied time-periodic ac and constant biasing dc currents is studied using the time dependent Ginzburg-Landau formalism with a Lawrence-Doniach extension. At zero external magnetic field and dc biasing current the resistive state of the system is characterized by periodic nucleation and annihilation of fluxon-antifluxon pairs, relative positions of which are determined by the state of neighboring junctions. Due to the mutual repulsive interaction, fluxons in different junctions move out of phase. Their collective motion can be synchronized by adding a small ac component to the biasing dc current. Coherent motion of fluxons is observed for a broad frequency range of the applied drive. In the coherent state the maximal output voltage, which is proportional to the number of junctions in the stack, is observed near the characteristic frequency of the system determined by the crossing of the fluxons across the sample. However, in this frequency range the dynamically synchronized state has an alternative-a less ordered state with smaller amplitude of the output voltage. Collective behavior of the junctions is strongly affected by the sloped sidewalls of the stack. Synchronization is observed only for weakly trapezoidal cross sections, whereas irregular motion of fluxons is observed for larger slopes of the sample edge.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 10
DOI: 10.1103/PhysRevB.87.184510
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“Effect of sample geometry on the phase boundary of a mesoscopic superconducting loop”. Berdiyorov GR, Yu SH, Xiao ZL, Peeters FM, Hua J, Imre A, Kwok WK, Physical review : B : solid state 80, 064511 (2009). http://doi.org/10.1103/PhysRevB.80.064511
Abstract: We studied the effect of sample geometry on the evolution of the superconducting state in nanoscale Nb circular and square loops by transport measurements. A multistage resistive transition with temperature is found for both samples, which is related to the effect of contact leads made from the same superconducting material. The H-T phase diagrams close to Tc0 show clear periodic oscillations on top of a parabolic background, i.e., Little-Parks effect. However, the amplitude of the oscillations decreases faster in the circular loop compared to the one in the square sample. Numerical simulations are conducted within the nonlinear Ginzburg-Landau theory to show the effect of sample geometry on the nucleation of superconductivity in superconducting loop structures.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 21
DOI: 10.1103/PhysRevB.80.064511
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“Ginzburg-Landau theory and effects of pressure on a two-band superconductor : application to MgB2”. Betouras JJ, Ivanov VA, Peeters FM, European physical journal : B : condensed matter and complex systems 31, 349 (2003). http://doi.org/10.1140/epjb/e2003-00041-7
Abstract: We present a model of pressure effects of a two-band superconductor based on a Ginzburg-Landau free energy with two order parameters. The parameters of the theory are pressure as well as temperature dependent. New pressure effects emerge as a result of the competition between the two bands. The theory then is applied to MgB2. We identify two possible scenaria regarding the fate of the two Q subbands under pressure, depending on whether or not both subbands are above the Fermi energy at ambient pressure. The splitting of the two subbands is probably caused by the E-2g, distortion. If only one subband is above the Fermi energy at ambient pressure (scenario I), application of pressure diminishes the splitting and it is possible that the lower subband participates in the superconductivity. The corresponding crossover pressure and Gruneisen parameter are estimated. In the second scenario both bands start above the Fermi energy and they move below it, either by pressure or via the substitution of Mg by Al. In both scenaria, the possibility of electronical topological transition is emphasized. Experimental signatures of both scenaria are presented and existing experiments are discussed in the light of the different physical pictures.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.461
Times cited: 10
DOI: 10.1140/epjb/e2003-00041-7
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“Magneto-oscillations of the gate current in a laterally modulated two-dimensional electron gas”. Blom FAP, Peeters FM, van de Zanden K, van Hove M, Surface science : a journal devoted to the physics and chemistry of interfaces 361/362, 851 (1996). http://doi.org/10.1016/0039-6028(96)00549-3
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.925
Times cited: 1
DOI: 10.1016/0039-6028(96)00549-3
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“Quantum oscillations in the Hall effect of thin Sc1-xErxAs epitaxial layers burried in GaAs”. Bogaerts R, de Keyser A, Herlach F, Peeters FM, DeRosa F, Palmstrøm CJ, Brehmer D, Allen SJ, , 596 (1995)
Keywords: P3 Proceeding; Condensed Matter Theory (CMT)
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“Size effects in the transport properties of thin Sc1-xErxAs epitaxial layers buried in GaAs”. Bogaerts R, de Keyser A, Herlach F, Peeters FM, DeRosa F, Palmstrøm CJ, Brehmer D, Allen SJ, Solid state electronics 37, 789 (1994). http://doi.org/10.1016/0038-1101(94)90299-2
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.504
Times cited: 4
DOI: 10.1016/0038-1101(94)90299-2
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“Magnetic freeze-out induced transition from three- to two-dimensional magnetotransport in Si-δ-doped InSb layers grown on GaAs”. Bogaerts R, de Keyser A, van Bockstal L, Herlach F, Karavolas VC, Peeters FM, Borghs G, , 706 (1995)
Keywords: P3 Proceeding; Condensed Matter Theory (CMT)
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“2D semiconductors at the Leuven pulsed field facility”. Bogaerts R, de Keyser A, van Bockstal L, van der Burgt M, van Esch A, Provoost R, Silverans R, Herlach F, Swinnen B, van de Stadt AFW, Koenraad PM, Wolter JH, Karavolas VC, Peeters FM, van de Graaf W, Borghs G, Physicalia magazine 19, 229 (1997)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
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“Experimental determination of the Fermi surface of thin Sc1-xErxAs epitaxial layers in pulsed magnetic fields”. Bogaerts R, Herlach F, de Keyser A, Peeters FM, DeRosa F, Palmstrøm CJ, Brehmer D, Allen SJ, Physical review : B : condensed matter and materials physics 53, 15951 (1996). http://doi.org/10.1103/PhysRevB.53.15951
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.736
Times cited: 9
DOI: 10.1103/PhysRevB.53.15951
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“Magnetotransport measurements on thin Ga1-xErxAs epitaxial films in pulsed magnetic fields”. Bogaerts R, van Bockstal L, Herlach F, Peeters FM, DeRosa F, Palmstrøm CJ, Allen SJ, Physica: B : condensed matter 177, 425 (1992). http://doi.org/10.1016/0921-4526(92)90142-F
Abstract: Magnet0transport measurements in pulsed fields up to 46 T and at temperatures between 1.4 and 210 K have been performed on thin semimetallic epitaxial layers of Sc1-xErxAs buried inside insulating GaAs. A consistent description is obtained of the magnetic field dependence of the Hall resistance and the different frequencies of the Shubnikov-de Hass oscillations.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.319
Times cited: 12
DOI: 10.1016/0921-4526(92)90142-F
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“Experimental study of the energy band structure of Sc1-xErxAs layers in pulsed magnetic fields”. Bogaerts R, van Esch A, van Bockstal L, Herlach F, Peeters FM, DeRosa F, Palmstrøm CJ, Allen SJ, Physica: B : condensed matter 184, 232 (1993). http://doi.org/10.1016/0921-4526(93)90356-B
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.319
Times cited: 9
DOI: 10.1016/0921-4526(93)90356-B
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“Electric-field manipulation of spin states in confined non-magnetic/magnetic heterostructures”. Borza S, Peeters FM, Vasilopoulos P, Papp G, Journal of physics : condensed matter 19, 176221 (2007). http://doi.org/10.1088/0953-8984/19/17/176221
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 4
DOI: 10.1088/0953-8984/19/17/176221
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“Transport detection of quantum Hall fluctuations in graphene”. Branchaud S, Kam A, Zawadzki P, Peeters FM, Sachrajda AS, Physical review : B : condensed matter and materials physics 81, 121406 (2010). http://doi.org/10.1103/PhysRevB.81.121406
Abstract: Low-temperature magnetoconductance measurements were made in the vicinity of the charge neutrality point (CNP). Two origins for the fluctuations were identified close to the CNP. At very low magnetic fields there exist only mesoscopic magnetoconductance quantum interference features which develop rapidly as a function of density. At slightly higher fields (>0.5 T), close to the CNP, additional fluctuations track the quantum Hall (QH) sequence expected for monolayer graphene. These additional features are attributed to effects of locally charging individual QH localized states. These effects reveal a precursor to the quantum Hall effect since, unlike previous transport observations of QH dot charging effects, they occur in the absence of quantum Hall plateaus or Shubnikov-de Haas oscillations. From our transport data we are able to extract parameters that characterize the inhomogeneities in our device.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 25
DOI: 10.1103/PhysRevB.81.121406
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“Quantum effects in a free-standing graphene lattice : path-integral against classical Monte Carlo simulations”. Brito BGA, Candido L, Hai G-Q, Peeters FM, Physical review : B : condensed matter and materials physics 92, 195416 (2015). http://doi.org/10.1103/PhysRevB.92.195416
Abstract: In order to study quantum effects in a two-dimensional crystal lattice of a free-standing monolayer graphene, we have performed both path-integral Monte Carlo (PIMC) and classical Monte Carlo (MC) simulations for temperatures up to 2000 K. The REBO potential is used for the interatomic interaction. The total energy, interatomic distance, root-mean-square displacement of the atom vibrations, and the free energy of the graphene layer are calculated. The obtained lattice vibrational energy per atom from the classical MC simulation is very close to the energy of a three-dimensional harmonic oscillator 3k(B)T. The PIMC simulation shows that quantum effects due to zero-point vibrations are significant for temperatures T < 1000 K. The quantum contribution to the lattice vibrational energy becomes larger than that of the classical lattice for T < 400 K. The lattice expansion due to the zero-point motion causes an increase of 0.53% in the lattice parameter. A minimum in the lattice parameter appears at T similar or equal to 500 K. Quantum effects on the atomic vibration amplitude of the graphene lattice and its free energy are investigated.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 22
DOI: 10.1103/PhysRevB.92.195416
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“Liber amicorum in honour of Jozef T. Devreese”. Brosens F, Fomin VM, Lemmens L, Peeters FM Wiley, Weinheim (2003).
Keywords: ME3 Book as editor; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
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“High energy transitions and phonon-assisted harmonics of a shallow magneto-donor in GaAs/AlGaAs multiple quantum wells”. Bruno-Alfonso A, Hai G-Q, Peeters FM, Yeo T, Ryu SR, McCombe BD, , 1413 (2001)
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“High energy transitions of shallow magneto-donors in a GaAs/Al0.3Ga0.7As multiple quantum well”. Bruno-Alfonso A, Hai G-Q, Peeters FM, Yeo T, Ryu SR, McCombe BD, Journal of physics : condensed matter 13, 9761 (2001). http://doi.org/10.1088/0953-8984/13/43/307
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
Times cited: 7
DOI: 10.1088/0953-8984/13/43/307
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“From vortex molecules to the Abrikosov lattice in thin mesoscopic superconducting disks”. Cabral LRE, Baelus BJ, Peeters FM, Physical review : B : condensed matter and materials physics 70, 144523 (2004). http://doi.org/10.1103/PhysRevB.70.144523
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 71
DOI: 10.1103/PhysRevB.70.144523
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“Two-shell vortex and antivortex dynamics in a Corbino superconducting disk”. Cabral LRE, de Aquino BRCHT, de Souza Silva CC, Milošević, MV, Peeters FM, Physical review : B : condensed matter and materials physics 93, 014515 (2016). http://doi.org/10.1103/PhysRevB.93.014515
Abstract: We examine theoretically the dynamics of two vortex shells in pinning-free superconducting thin disks in the Corbino geometry. In the first considered case, the inner shell is composed of vortices and the outer one of antivortices, corresponding to a state induced by the stray field of an off-plane magnetic dipole placed on top of the superconductor. In the second considered case, both shells comprise vortices induced by a homogeneous external field. We derive the equation of motion for each shell within the Bardeen-Stephen model and study the dynamics analytically by assuming both shells are rigid and commensurate. In both cases, two distinct regimes for vortex shell motion are identified: For low applied currents the entire configuration rotates rigidly, while above a threshold current the shells decouple from each other and rotate at different angular velocities. Analytical expressions for the decoupling current, the recombination time in the decoupled phases, as well as the voltage-current characteristics are presented. Our analytical results are in excellent agreement with numerical molecular dynamics simulations of the full many-vortex problem.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 7
DOI: 10.1103/PhysRevB.93.014515
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“Elastic modes of vortex configurations in thin disks”. Cabral LRE, Peeters FM, Physical review : B : condensed matter and materials physics 70, 214522 (2004). http://doi.org/10.1103/PhysRevB.70.214522
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 6
DOI: 10.1103/PhysRevB.70.214522
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“Photoaccelerated water dissociation across one-atom-thick electrodes”. Cai J, Griffin E, Guarochico-Moreira V, Barry D, Xin B, Huang S, Geim AK, Peeters FM, Lozada-Hidalgo M, Nano letters 22, 9566 (2022). http://doi.org/10.1021/ACS.NANOLETT.2C03701
Abstract: Recent experiments demonstrated that interfacial water dissociation (H2O ⇆ H+ + OH-) could be accelerated exponentially by an electric field applied to graphene electrodes, a phenomenon related to the Wien effect. Here we report an order-of-magnitude acceleration of the interfacial water dissociation reaction under visible-light illumination. This process is accompanied by spatial separation of protons and hydroxide ions across one-atom-thick graphene and enhanced by strong interfacial electric fields. The found photoeffect is attributed to the combination of graphene's perfect selectivity with respect to protons, which prevents proton-hydroxide recombination, and to proton transport acceleration by the Wien effect, which occurs in synchrony with the water dissociation reaction. Our findings provide fundamental insights into ion dynamics near atomically thin proton-selective interfaces and suggest that strong interfacial fields can enhance and tune very fast ionic processes, which is of relevance for applications in photocatalysis and designing reconfigurable materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 10.8
Times cited: 3
DOI: 10.1021/ACS.NANOLETT.2C03701
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“Wien effect in interfacial water dissociation through proton-permeable graphene electrodes”. Cai J, Griffin E, Guarochico-Moreira VH, Barry D, Xin B, Yagmurcukardes M, Zhang S, Geim AK, Peeters FM, Lozada-Hidalgo M, Nature communications 13, 5776 (2022). http://doi.org/10.1038/S41467-022-33451-1
Abstract: Strong electric fields can accelerate molecular dissociation reactions. The phenomenon known as the Wien effect was previously observed using high-voltage electrolysis cells that produced fields of about 10(7) V m(-1), sufficient to accelerate the dissociation of weakly bound molecules (e.g., organics and weak electrolytes). The observation of the Wien effect for the common case of water dissociation (H2O reversible arrow H+ + OH-) has remained elusive. Here we study the dissociation of interfacial water adjacent to proton-permeable graphene electrodes and observe strong acceleration of the reaction in fields reaching above 10(8) V m(-1). The use of graphene electrodes allows measuring the proton currents arising exclusively from the dissociation of interfacial water, while the electric field driving the reaction is monitored through the carrier density induced in graphene by the same field. The observed exponential increase in proton currents is in quantitative agreement with Onsager's theory. Our results also demonstrate that graphene electrodes can be valuable for the investigation of various interfacial phenomena involving proton transport.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 16.6
Times cited: 14
DOI: 10.1038/S41467-022-33451-1
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“Realization of a p-n junction in a single layer boron-phosphide”. Çakir D, Kecik D, Sahin H, Durgun E, Peeters FM, Physical chemistry, chemical physics 17, 13013 (2015). http://doi.org/10.1039/c5cp00414d
Abstract: Two-dimensional (2D) materials have attracted growing interest due to their potential use in the next generation of nanoelectronic and optoelectronic applications. On the basis of first-principles calculations based on density functional theory, we first investigate the electronic and mechanical properties of single layer boron phosphide (h-BP). Our calculations show that h-BP is a mechanically stable 2D material with a direct band gap of 0.9 eV at the K-point, promising for both electronic and optoelectronic applications. We next investigate the electron transport properties of a p-n junction constructed from single layer boron phosphide (h-BP) using the non-equilibrium Green's function formalism. The n-and p-type doping of BP are achieved by substitutional doping of B with C and P with Si, respectively. C(Si) substitutional doping creates donor (acceptor) states close to the conduction (valence) band edge of BP, which are essential to construct an efficient p-n junction. By modifying the structure and doping concentration, it is possible to tune the electronic and transport properties of the p-n junction which exhibits not only diode characteristics with a large current rectification but also negative differential resistance (NDR). The degree of NDR can be easily tuned via device engineering.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.123
Times cited: 104
DOI: 10.1039/c5cp00414d
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“Dependence of the electronic and transport properties of metal-MoSe2 interfaces on contact structures”. Çakir D, Peeters FM, Physical review : B : condensed matter and materials physics 89, 245403 (2014). http://doi.org/10.1103/PhysRevB.89.245403
Abstract: Transition metal dichalcogenides (TMDs) are considered as promising candidates for next generation of electronic and optoelectronic devices. To make use of these materials, for instance in field effect transistor applications, it is mandatory to know the detailed properties of contacts of such TMDs with metal electrodes. Here, we investigate the role of the contact structure on the electronic and transport properties of metal-MoSe2 interfaces. Two different contact types, namely face and edge contacts, are studied. We consider both low (Sc) and high (Au) work function metals in order to thoroughly elucidate the role of the metal work function and the type of metal. First principles plane wave calculations and transport calculations based on nonequilibrium Green's function formalism reveal that the contact type has a large impact on the electronic and transport properties of metal-MoSe2 interfaces. For the Sc electrode, the Schottky barrier heights are around 0.25 eV for face contact and bigger than 0.6 eV for edge contact. For the Au case, we calculate very similar barrier heights for both contact types with an average value of 0.5 eV. Furthermore, while the face contact is found to be highly advantageous as compared to the edge contact for the Sc electrode, the latter contact becomes a better choice for the Au electrode. Our findings provide guidelines for the fabrication of TMD-based devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 39
DOI: 10.1103/PhysRevB.89.245403
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“Fluorographane : a promising material for bipolar doping of MoS2”. Çakir D, Peeters FM, Physical chemistry, chemical physics 17, 27636 (2015). http://doi.org/10.1039/c5cp04438c
Abstract: Using first principles calculations we investigate the structural and electronic properties of interfaces between fluorographane and MoS2. Unsymmetrical functionalization of graphene with H and F results in an intrinsic dipole moment perpendicular to the plane of the buckled graphene skeleton. Depending on the orientation of this dipole moment, the electronic properties of a physically absorbed MoS2 monolayer can be switched from n-to p-type or vice versa. We show that one can realize vanishing n-type/p-type Schottky barrier heights when contacting MoS2 to fluorographane. By applying a perpendicular electric field, the size of the Schottky barrier and the degree of doping can be tuned. Our calculations indicate that a fluorographane monolayer is a promising candidate for bipolar doping of MoS2, which is vital in the design of novel technological applications based on two-dimensional materials.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 4.123
Times cited: 7
DOI: 10.1039/c5cp04438c
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“Mechanical and thermal properties of h-MX2 (M = Cr, Mo, W, X = O, S, Se, Te) monolayers : a comparative study”. Çakir D, Peeters FM, Sevik C, Applied physics letters 104, 203110 (2014). http://doi.org/10.1063/1.4879543
Abstract: Using density functional theory, we obtain the mechanical and thermal properties of MX2 monolayers (where M = Cr, Mo, W and X = O, S, Se, Te). The C-centered phonon frequencies (i.e., A(1), A(2)'', E ', and E ''), relative frequency values of A(1), and E ' modes, and mechanical properties (i.e., elastic constants, Young modulus, and Poisson's ratio) display a strong dependence on the type of metal and chalcogenide atoms. In each chalcogenide (metal) group, transition-metal dichalcogenides (TMDCs) with W (O) atom are found to be much stiffer. Consistent with their stability, the thermal expansion of lattice constants for TMDCs with O (Te) is much slower (faster). Furthermore, in a heterostructure of these materials, the difference of the thermal expansion of lattice constants between the individual components becomes quite tiny over the whole temperature range. The calculated mechanical and thermal properties show that TMDCs are promising materials for heterostructures. (C) 2014 AIP Publishing LLC.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.411
Times cited: 130
DOI: 10.1063/1.4879543
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