“DIY measurement of your personal HRTF at home : low-cost, fast and validated”. Reijniers J, Partoens B, Peremans H, , 1 (2017)
Abstract: <script type='text/javascript'>document.write(unpmarked('The breakthrough of 3D audio has been hampered by the lack of personalized head-related transfer functions (HRTF) required to create realistic 3D audio environments using headphones. In this paper we present a new method for the user to personalize his/her HRTF, similar to the measurement in an anechoic room, yet it is low-cost and can be carried out at home. We compare the resulting HRTFs with those measured in an anechoic room. Subjecting the participants to a virtual localization experiment, we show that they perform significantly better when using their personalized HRTF, compared to a generic HRTF. We believe this method has the potential of opening the way for large scale commercial use of 3D audio through headphones.'));
Keywords: P3 Proceeding; Engineering sciences. Technology; Engineering Management (ENM); Condensed Matter Theory (CMT)
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“Effect of zinc oxide modification by indium oxide on microstructure, adsorbed surface species, and sensitivity to CO”. Marikutsa A, Rumyantseva M, Gaskov A, Batuk M, Hadermann J, Sarmadian N, Saniz R, Partoens B, Lamoen D, Frontiers in materials 6 (2019). http://doi.org/10.3389/FMATS.2019.00043
Abstract: Additives in semiconductor metal oxides are commonly used to improve sensing behavior of gas sensors. Due to complicated effects of additives on the materials microstructure, adsorption sites and reactivity to target gases the sensing mechanism with modified metal oxides is a matter of thorough research. Herein, we establish the promoting effect of nanocrystalline zinc oxide modification by 1-7 at.% of indium on the sensitivity to CO gas due to improved nanostructure dispersion and concentration of active sites. The sensing materials were synthesized via an aqueous coprecipitation route. Materials composition, particle size and BET area were evaluated using X-ray diffraction, nitrogen adsorption isotherms, high-resolution electron microscopy techniques and EDX-mapping. Surface species of chemisorbed oxygen, OH-groups, and acid sites were characterized by probe molecule techniques and infrared spectroscopy. It was found that particle size of zinc oxide decreased and the BET area increased with the amount of indium oxide. The additive was observed as amorphous indium oxide segregated on agglomerated ZnO nanocrystals. The measured concentration of surface species was higher on In2O3-modified zinc oxide. With the increase of indium oxide content, the sensor response of ZnO/In2O3 to CO was improved. Using in situ infrared spectroscopy, it was shown that oxidation of CO molecules was enhanced on the modified zinc oxide surface. The effect of modifier was attributed to promotion of surface OH-groups and enhancement of CO oxidation on the segregated indium ions, as suggested by DFT in previous work.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Times cited: 11
DOI: 10.3389/FMATS.2019.00043
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“The work function of few-layer graphene”. Leenaerts O, Partoens B, Peeters FM, Volodin A, van Haesendonck C, Journal of physics : condensed matter 29, 035003 (2017). http://doi.org/10.1088/0953-8984/29/3/035003
Abstract: A theoretical and experimental study of the work function of few-layer graphene is reported. The influence of the number of layers on the work function is investigated in the presence of a substrate, a molecular dipole layer, and combinations of the two. The work function of few-layer graphene is almost independent of the number of layers with only a difference between monolayer and multilayer graphene of about 60 meV. In the presence of a charge-donating substrate the charge distribution is found to decay exponentially away from the substrate and this is directly reflected in the work function of few-layer graphene. A dipole layer changes the work function only when placed in between the substrate and few-layer graphene through a change of the charge transfer between the two.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 61
DOI: 10.1088/0953-8984/29/3/035003
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“Comparative analysis of tight-binding models for transition metal dichalcogenides”. Jorissen B, Covaci L, Partoens B, SciPost physics core 7, 004 (2024). http://doi.org/10.21468/SCIPOSTPHYSCORE.7.1.004
Abstract: We provide a comprehensive analysis of the prominent tight-binding (TB) models for transition metal dichalcogenides (TMDs) available in the literature. We inspect the construction of these TB models, discuss their parameterization used and conduct a thorough comparison of their effectiveness in capturing important electronic properties. Based on these insights, we propose a novel TB model for TMDs designed for enhanced computational efficiency. Utilizing MoS2 as a representative case, we explain why specific models offer a more accurate description. Our primary aim is to assist researchers in choosing the most appropriate TB model for their calculations on TMDs.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
DOI: 10.21468/SCIPOSTPHYSCORE.7.1.004
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“Noise-resistant correlation-based alignment of head-related transfer functions for high-fidelity spherical harmonics representation”. Reijniers J, Partoens B, Peremans H, (2023)
Abstract: It is standard practice in virtual reality applications to synthesize binaural audio based on a discrete set of directionally-dependent head-related impulse responses (HRIRs). This set of HRIRs is often time-aligned in a pre-processing step, to allow for high-fidelity interpolation between HRIRs corresponding with neighbouring directions. The fidelity of this operation depends on the similarity of neighbouring aligned HRIRs. The pairwise quality of similarity makes it a difficult criterion to optimize globally and consequently one often resorts to alignment methods based on a specific feature that can be extracted for each HRIR separately, e.g., the first-onset of the peak or the group delay. However, such proxies for similarity are very sensitive to noise and therefore require a high signal-to-noise ratio, which makes them less suitable for processing HRIRs acquired outside an anechoic room. In this paper, we advance a novel alignment method, which maximizes the similarity – defined as the correlation between the full-length HRIRs – between neighbouring aligned HRIRs for all directions at once. We show that this correlation-based alignment procedure outperforms the first-onset alignment with regards to the fidelity of the spherical harmonics representation of both the spectral and interaural time difference (ITD) information, when tested on the KEMAR HRIR and six human HRIRs. Finally, we show that the correlation-based alignment is more robust to noise.
Keywords: P3 Proceeding; Engineering sciences. Technology; Engineering Management (ENM); Condensed Matter Theory (CMT)
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“Accurate description of the van der Waals interaction of an electron-positron pair with the surface of a topological insulator”. Saniz R, Vercauteren S, Lamoen D, Partoens B, Barbiellini B, Journal of physics : conference series 505, 012002 (2014). http://doi.org/10.1088/1742-6596/505/1/012002
Abstract: Positrons can be trapped in localized states at the surface of a material, and thus quite selectively interact with core or valence surface electrons. Hence, advanced surface positron spectroscopy techniques can present the ideal tools to study a topological insulator, where surface states play a fundamental role. We analyze the problem of a positron at a TI surface, assuming that it is a weakly physisorbed positronium (Ps) atom. To determine if the surface of interest in a material can sustain such a physisorption, an accurate description of the underlying van der Waals (vdW) interaction is essential. We have developed a first-principles parameterfree method, based on the density functional theory, to extract key parameters determining the vdW interaction potential between a Ps atom and the surface of a given material. The method has been successfully applied to quartz and preliminary results on Bi2Te2Se indicate the existence of a positron surface state. We discuss the robustness of our predictions versus the most relevant approximations involved in our approach.
Keywords: P1 Proceeding; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Times cited: 2
DOI: 10.1088/1742-6596/505/1/012002
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“Artificial atoms and molecules”. Partoens B, Peeters FM, Physicalia magazine 24, 29 (2002)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
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“Branch current behavior at two level anti-crossings in vertical quantum dot single-particle spectra”. Payette C, Austing DG, Yu G, Gupta JA, Nair SV, Partoens B, Amaha S, Tarucha S, AIP conference proceedings 1199, 271 (2010). http://doi.org/10.1063/1.3295404
Abstract: We study single-electron-elastic-resonant-tunneling through two weakly coupled vertical quantum dots and investigate the branch current behavior at anti-crossings between two single-particle energy levels in the constituent dot spectra that are induced to approach each other by application of an out-of-dot-plane magnetic field. We observe both the familiar case of monotonic transfer of the resonant current strengths between the two branches as well as the less familiar case of concurrent enhancement and suppression (ideally complete cancellation) of the resonant current in the two branches. These two situations can be explained in terms of a simple coherent tunneling model. ©2009 American Institute of Physics
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1063/1.3295404
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“Characterization and modeling of single-particle energy levels and resonant currents in a coherent quantum dot mixer”. Austing DG, Payette C, Yu G, Gupta JA, Aers GC, Nair SV, Partoens B, Amaha S, Tarucha S, AIP conference proceedings
T2 –, 30th International Conference on the Physics of Semiconductors (ICPS-30), JUL 25-30, 2010, Seoul, SOUTH KOREA , 1 (2011). http://doi.org/10.1063/1.3666692
Abstract: We characterize and model the single-particle energy level position and resonant current strength at a three-level crossing in a coherent mixer composed of two weakly coupled vertical quantum dots. In addition to clear anticrossing behavior, an otherwise strong resonance is completely extinguished at the center of the crossing. Despite the strong variation in energy level position and resonant current strength throughout the crossing region, the resonance widths and the sum of the branch currents are found to be approximately constant.
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
DOI: 10.1063/1.3666692
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“Classical atomic bilayers”. Peeters FM, Partoens B, Schweigert VA, Schweigert IV Plenum Press, New York, page 523 (1998).
Keywords: H1 Book chapter; Condensed Matter Theory (CMT)
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“The classical electron gas in artificial structures”. Peeters FM, Partoens B, Kong M, , 235 (2004)
Keywords: P3 Proceeding; Condensed Matter Theory (CMT)
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“Density functional theory approach to artificial molecules”. Partoens B, Peeters FM, , 128 (2001)
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Electric field tuning of the band gap in four layers of graphene with different stacking order”. Avetisyan AA, Partoens B, Peeters FM, Proceedings of the Society of Photo-optical Instrumentation Engineers
T2 –, Conference on Photonics and Micro and Nano-structured Materials, JUN 28-30, 2011, Yerevan, ARMENIA , 84140 (2012). http://doi.org/10.1117/12.923618
Abstract: We investigated the effect of different stacking order of the four graphene layer system on the induced band gap when positively charged top and negatively charged back gates are applied to the system. A tight-binding approach within a self-consistent Hartree approximation is used to calculate the induced charges on the different graphene layers. We show that the electric field does not open an energy gap if the multilayer graphene system contains a trilayer part with the ABA Bernal stacking.
Keywords: P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT)
DOI: 10.1117/12.923618
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“Enhanced spin and isospin blockade in two vertically coupled quantum dots”. Partoens B, Peeters FM, , 1035 (2001)
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Excitons and trions in cylindrical nanowires with dielectric mismatch”. Slachmuylders AF, Partoens B, Magnus W, Peeters FM, Physica status solidi: C: conferences and critical reviews 5, 2416 (2008). http://doi.org/10.1002/pssc.200777650
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 3
DOI: 10.1002/pssc.200777650
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“Excitons in single and vertically coupled type II quantum dots in high magnetic fields”. Peeters FM, Janssens KL, Partoens B s.l., page 117 (2003).
Keywords: H1 Book chapter; Condensed Matter Theory (CMT)
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“Geometry induced defects in a confined Wigner lattice”. Peeters FM, Kong M, Partoens B, , 192 (2002)
Keywords: P1 Proceeding; Condensed Matter Theory (CMT)
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“Ground state configurations of vertically coupled quantum rings”. Castelano LK, Hai G-Q, Partoens B, Peeters FM, Physica status solidi: C: conferences and critical reviews 4, 560 (2007). http://doi.org/10.1002/pssc.200673275
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 1
DOI: 10.1002/pssc.200673275
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“Hole band engineering in self-assembled quantum dots and molecules”. Peeters FM, Tadić M, Janssens KL, Partoens B s.l., page 191 (2004).
Keywords: H1 Book chapter; Condensed Matter Theory (CMT)
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“Magneto-exciton in single and coupled type II quantum dots”. Janssens KL, Partoens B, Peeters FM, Physica status solidi: A: applied research 190, 571 (2002). http://doi.org/10.1002/1521-396X(200204)190:2<571::AID-PSSA571>3.0.CO;2-K
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1002/1521-396X(200204)190:2<571::AID-PSSA571>3.0.CO;2-K
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“Magnetoplasma excitations in vertically coupled quantum dot systems”. Partoens B, Matulis A, Peeters FM, Materials science forum 297/298, 225 (1999)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
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“Phonon band structures of Si nanowires”. Peelaers H, Partoens B, Peeters FM, AIP conference proceedings 1199, 323 (2009). http://doi.org/10.1063/1.3295432
Abstract: We present full ab initio calculations of the phonon band structure of thin Si nanowires oriented along the [110] direction. Using these phonon dispersion relations we investigate the structural stability of these wires. We found that all studied wires were stable also when doped with either B or P, if the unit cell was taken sufficiently large along the wire axis. The evolution of the phonon dispersion relations and of the sound velocities with respect to the wire diameters is discussed. Softening is observed for acoustic modes and hardening for optical phonon modes with increasing wire diameters.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1063/1.3295432
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“Scheme for coherently quenching resonant current in a three-level quantum dot energy level mixer”. Austing DG, Payette C, Nair SV, Yu G, Gupta JA, Partoens B, Amaha S, Tarucha S, Physica status solidi: C: conferences and critical reviews 6, 940 (2009). http://doi.org/10.1002/pssc.200880584
Abstract: We outline a scheme to create a dark state by three-level mixing that is potentially a useful tool for quantum coherent transport. Magnetic-field-induced intra-dot level mixing can lead to rich quantum superposition phenomena between three approaching single-particle states in a quantum dot when probed by the ground state of an adjacent weakly coupled quantum dot in the single-electron resonant tunnelling regime. The mixing relies on non-negligible anharmonicity and anisotropy in confining potentials of realistic quantum dots. Anti-crossing and transfer of strengths between resonances can be understood with a simple coherent level mixing model. Superposition can lead to the formation of a dark state by complete cancellation of an otherwise strong resonance. This is an all-electrical analogue of coherent population trapping seen in three-level-systems from quantum and atom optics.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1002/pssc.200880584
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“Single and coupled type II quantum dots in magnetic and electric fields”. Janssens KL, Partoens B, Peeters FM, Physicalia magazine 24, 211 (2002)
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
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“Surface states and positron annihilation spectroscopy: results and prospects from a first-principles approach”. Callewaert V, Saniz R, Barbiellini B, Partoens B, Journal of physics : conference series 791, 012036 (2017). http://doi.org/10.1088/1742-6596/791/1/012036
Abstract: The trapping of positrons at the surface of a material can be exploited to study quite selectively the surface properties of the latter by means of positron annihilation spectroscopy techniques. To support these, it is desirable to be able to theoretically predict the existence of such positronic surface states and to describe their annihilation characteristics with core or valence surface electrons in a reliable way. Here, we build on the well-developed first-principles techniques for the study of positrons in bulk solids as well as on previous models for surfaces, and investigate two schemes that can improve the theoretical description of the interaction of positrons with surfaces. One is based on supplementing the local-density correlation potential with the corrugated image potential at the surface, and the other is based on the weighted-density approximation to correlation. We discuss our results for topological insulators, graphene layers, and quantum dots, with emphasis on the information that can be directly related to experiment. We also discuss some open theoretical problems that should be addressed by future research.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 1
DOI: 10.1088/1742-6596/791/1/012036
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“New insights into the nanostructure of innovative thin film solar cells gained by positron annihilation spectroscopy”. Eijt SWH, Shi W, Mannheim A, Butterling M, Schut H, Egger W, Dickmann M, Hugenschmidt C, Shakeri B, Meulenberg RW, Callewaert V, Saniz R, Partoens B, Barbiellini B, Bansil A, Melskens J, Zeman M, Smets AHM, Kulbak M, Hodes G, Cahen D, Brück E, Journal of physics : conference series 791, 012021 (2017). http://doi.org/10.1088/1742-6596/791/1/012021
Abstract: Recent studies showed that positron annihilation methods can provide key insights into the nanostructure and electronic structure of thin film solar cells. In this study, positron annihilation lifetime spectroscopy (PALS) is applied to investigate CdSe quantum dot (QD) light absorbing layers, providing evidence of positron trapping at the surfaces of the QDs. This enables one to monitor their surface composition and electronic structure. Further, 2D-Angular Correlation of Annihilation Radiation (2D-ACAR) is used to investigate the nanostructure of divacancies in photovoltaic-high-quality a-Si:H films. The collected momentum distributions were converted by Fourier transformation to the direct space representation of the electron-positron autocorrelation function. The evolution of the size of the divacancies as a function of hydrogen dilution during deposition of a-Si:H thin films was examined. Finally, we present a first positron Doppler Broadening of Annihilation Radiation (DBAR) study of the emerging class of highly efficient thin film solar cells based on perovskites.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 1
DOI: 10.1088/1742-6596/791/1/012021
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“First-Principles Investigation of the Stability of the Oxygen Framework of Li-Rich Battery Cathodes”. Bercx M, Slap L, Partoens B, Lamoen D, MRS advances 4, 813 (2019). http://doi.org/10.1557/adv.2019.135
Abstract: Lithium-rich layered oxides such as Li<sub>2</sub>MnO<sub>3</sub>have shown great potential as cathodes in Li-ion batteries, mainly because of their large capacities. However, these materials still suffer from structural degradation as the battery is cycled, reducing the average voltage and capacity of the cell. The voltage fade is believed to be related to the migration of transition metals into the lithium layer, linked to the formation of O-O dimers with a short bond length, which in turn is driven by the presence of oxygen holes due to the participation of oxygen in the redox process. We investigate the formation of O-O dimers for partially charged O1-Li<sub>2</sub>MnO<sub>3</sub>using a first-principles density functional theory approach by calculating the reaction energy and kinetic barriers for dimer formation. Next, we perform similar calculations for partially charged O1-Li<sub>2</sub>IrO<sub>3</sub>, a Li-rich material for which the voltage fade was not observed during cycling. When we compare the stability of the oxygen framework, we conclude that the formation of O-O dimers is both thermodynamically and kinetically viable for O1-Li<sub>0.5</sub>MnO<sub>3</sub>. For O1-Li<sub>0.5</sub>IrO<sub>3</sub>, we observe that the oxygen lattice is much more stable, either returning to its original state when perturbed, or resulting in a structure with an O-O dimer that is much higher in energy. This can be explained by the mixed redox process for Li<sub>2</sub>IrO<sub>3</sub>, which is also shown from the calculated magnetic moments. The lack of O-O dimer formation in O1-Li<sub>0.5</sub>IrO<sub>3</sub>provides valuable insight as to why Li<sub>2</sub>IrO<sub>3</sub>does not demonstrate a voltage fade as the battery is cycled, which can be used to design Li-rich battery cathodes with an improved cycling performance.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Times cited: 3
DOI: 10.1557/adv.2019.135
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“Free-standing Si and Ge, and Ge/Si core-shell semiconductor nanowires”. Peelaers H, Partoens B, Peeters FM, Acta physica Polonica: A: general physics, solid state physics, applied physics
T2 –, WELCOME Scientific Meeting on Hybrid Nanostructures, AUG 28-31, 2011, Torun, POLAND 122, 294 (2012)
Abstract: The properties of free-standing silicon and germanium nanowires oriented along the [110] direction are studied using different first principles methods. We show the corrections due to quasi-particles to the band structures obtained using the local-density approximation. The formation energies of B and P doped nanowires are calculated, both in the absence and presence of dangling bond defects and we link these to experimental results. Furthermore, we report on the phonon properties of pure Si and Ge nanowires, as well as Ge/Si core-shell nanowires, and discuss the differences between them.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.469
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“Two vertically coupled quantum rings with tunneling”. Castelano LK, Hai GQ, Partoens B, Peeters FM, Brazilian journal of physics 36, 936 (2006). http://doi.org/10.1590/S0103-97332006000600037
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 0.732
Times cited: 2
DOI: 10.1590/S0103-97332006000600037
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“Magnetic field dependence of the normal mode spectrum of a planar complex plasma cluster”. Kong M, Ferreira WP, Partoens B, Peeters FM, IEEE transactions on plasma science 32, 569 (2004). http://doi.org/10.1109/TPS.2004.826084
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 1.052
Times cited: 4
DOI: 10.1109/TPS.2004.826084
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