Hole-hole Interaction Research Articles

Assessing acoustic performance of building material: A finite element model for 3D printed multilayer micro-perforated panels with compressed earth blocks

This study deals with 3D printing multilayered micro-perforated panels (M-MPPs) coupled with buildings materials as compressed earth block for noise reduction applications. The sound absorption coefficient α is utilized as a metric to assess the sound insulation capabilities across a frequency range spanning from 10 to 3000 Hz, then evaluated and validated by numerical and experimental methods. The FEM model developed makes it possible to predict the acoustic absorption of M-MPPs by tuning the frequency range and varying optimized acoustics parameters, considering hole-hole interaction and taking into account visco-thermal effects that are present in compressed earth blocks. It is shown that the shape of perforations and material properties including the porosity rate, arrangement in the design of multilayer micro-perforated structures are identified to play a significant role in the sound performance of the entire structure. In addition, the application of MPP coupled with compressed earth blocks improve the sound absorption capacity of the composite structure. The developed FEM leads to accurate prediction of performance, efficient optimization, and cost effectiveness. Finally, the present study reveals the importance of M-MPPs combined with compressed earth blocks (CEBs) as viable noise reduction materials, particularly relevant for engineering applications and development initiatives in emerging economies.

Drag Resistivity of Hole-Hole Static Interactions with the Effect of Non- Homogeneous Dielectric Medium

BACKGROUND: We have study the Coulomb drag phenomena for hole-hole static potentials theoretically and measured numerically using the random phase approximation (RPA) method OBJECTIVE: The drag resistivity is evaluated at low temperature, large interlayer separation limit and weakly screening regime, with the geometry of two atomically thin materials, such as, BLG/GaAs based multilayer system, is a promising systems in nanomaterials and technology METHOD: Static local field corrections (LFC) are considered to take into account the Exchange-correlations (XC) and mutual interaction effects with varying concentrations of active and passive layer RESULT: It is found that the drag resistivity is found enhanced on using the LFC effects and increases on increasing the effective mass. In Fermi-Liquid regime, drag resistivity is directly proportional to T^2, n^(-3), d^(-4) and ϵ^2 with respect to temperature (T), density (n), interlayer separation (d~nm) and dielectric constant (ϵ_2), respectively. CONCLUSION: Dependency of drag resistivity is measured and compared to 2D e-e and e-h coupled-layer systems with and without the effect of non-homogeneous dielectric medium.

Coexistence of two hole phases in high-quality p−GaAs/AlGaAs in the vicinity of Landau-level filling factors ν=1 and ν=(1/3)

We focused on the transverse AC magnetoconductance of a high-mobility $p$-GaAs/AlGaAs quantum well $(p=1.2\ifmmode\times\else\texttimes\fi{}{10}^{11}{\mathrm{cm}}^{\ensuremath{-}2})$ in the vicinity of two values of the Landau-level filling factor $\ensuremath{\nu}$: $\ensuremath{\nu}=1$ (integer quantum Hall effect) and $\ensuremath{\nu}=1/3$ (fractional quantum Hall effect). The complex transverse AC conductance ${\ensuremath{\sigma}}_{xx}^{\mathrm{AC}}(\ensuremath{\omega})$ was found from simultaneous measurements of attenuation and velocity of surface acoustic waves propagating along the interface between a piezoelectric crystal and the two-dimensional hole system under investigation. We analyzed both the real and imaginary parts of the hole conductance and compared the similarities and differences between the results for filling factor 1 and filling factor 1/3. Both to the left and to the right of these values maxima of a specific shape, ``wings,'' arose in the $\ensuremath{\sigma}(\ensuremath{\nu})$ dependences at those two $\ensuremath{\nu}$. Analysis of the results of our acoustic measurements at different temperatures and surface acoustic wave frequencies allowed us to attribute these wings to the formation of collective localized states, namely, the domains of a pinned Wigner crystal, i.e., a Wigner solid. While the Wigner solid has been observed in 2D hole systems previously, we were able to detect it at the highest hole density and, therefore, the lowest hole-hole interaction reported.

Effective shell-model interaction for nuclei “southeast” of Sn100

We construct an effective shell-model interaction for the valence space spanned by single-particle neutron and single-hole proton states in $^{100}$Sn. Starting from chiral nucleon-nucleon and three-nucleon forces and single-reference coupled-cluster theory for $^{100}$Sn we apply a second similarity transformation that decouples the valence space. The particle-particle components of the resulting effective interaction can be used in shell model calculations for neutron deficient tin isotopes. The hole-hole interaction can be used to calculate the $N = 50$ isotones south of $^{100}$Sn, and the full particle-hole interaction describes nuclei in the region southeast of $^{100}$Sn. We compute low-lying excited states in selected nuclei southeast of $^{100}$Sn, and find reasonable agreement with data. The presented techniques can also be applied to construct effective shell-model interactions for other regions of the nuclear chart.

Kondo holes in strongly correlated impurity arrays: RKKY-driven Kondo screening and hole-hole interactions

The emerging and screening of local magnetic moments in solids has been investigated for more than 60 years. Local vacancies as in graphene or in Heavy Fermions can induce decoupled bound states that lead to the formation of local moments. In this paper, we address the puzzling question how these local moments can be screened and what determines the additionally emerging low temperature scale. We review the initial problem for half-filled conduction bands from two complementary perspectives: By a single-particle supercell analysis in the uncorrelated limit and by the Lieb-Mathis theorem for systems with a large Coulomb interaction $U$. We proof that the stable local moments are subject to screening by three different mechanisms. Firstly the local moments are delocalized by a finite $U$ beyond the single-particle bound state. We find a Kosterlitz-Thouless type transition governed by an exponentially suppressed low energy scale of a counterintuitive Kondo form with $J_{\rm eff} \propto U^n$ for small $U$, where $n>1$ depends on the precise model. Secondly, we show that away from half-filling the local moment phase becomes unstable and is replaced by two types of singlet phases that are adiabatically connected. At a critical value for the band center, the physics is governed by an exponentially suppressed Kondo scale approaching the strong coupling phase that is replaced by an singlet formation via antiferromagnetic RKKY interaction for large deviation from the critical values. Thirdly, we show that the local magnetic moment can be screened by a Kondo hole orbital at finite energy, even though the orbital occupation is negligible: An additional low energy scale emerges below which the localized moment is quenched. Similarities to the experimental findings in Ce$_{1-x}$La$_x$Pd$_3$ are pointed out.

Defect Chemistry of Mixed Conducting Pcfc Cathode Materials with Protons, Oxygen Vacancies and Holes

In recent years significant progress was achieved for protonic ceramic fuel cells (PCFC) concerning fundamental understanding, materials processing, and device performance. PCFC cathode materials require sufficient proton conductivity to extend the reaction zone beyond the three phase boundary. The hydration thermodynamics of BaFeO3- d-related perovskites was studied using thermogravimetry.[1] Despite a high oxygen vacancy concentration, the degree of hydration is lower for cathode materials compared to Ba(Zr,Y)O3-x electrolytes. A partial substitution of iron by redox-inactive, oversized Zn2+ or Y3+ drastically increases the proton uptake. Measurements of oxygen nonstoichiometry and proton uptake indicate pronounced deviations from ideally dilute defect chemistry (assigned to hole-hole and hole-proton defect interactions [1]). Based on DFT calculations [2] and EXAFS/XRS measurements [3], these interactions are related to the partial transfer of electron holes from iron to adjacent oxygen ions, which in turn disfavors protonation. The obtained detailed defect-chemical understanding serves as the basis for further PCFC cathode optimization, in particular since proton uptake, catalytic activity, electronic conductivity, and stability show conflicting dependencies on cation composition.[1] R. Zohourian, R. Merkle, G. Raimondi, J. Maier, Adv. Funct. Mater. 28 (2018) 1801241.[2] M.F. Hoedl, D. Gryaznov, R. Merkle, E. A. Kotomin, J. Maier, J. Phys. Chem. C 124 (2020) 11780.[3] G. Raimondi, F. Giannici, A. Longo, R. Merkle, A. Chiara, M. F. Hoedl, A. Martorana, J. Maier, Chem. Mater. 32 (2020) 8502.We thank GIF (I-1342-302.5/2016) for financial support.Figure 1: (a) Increase of proton uptake by Y or Zn doping [1]. (b) Dependence of hydration enthalpy on formal Fe oxidation state [2]. (c) Increased local deformations by Y doping [3]. (d) Conflicting trends; e.g. Ba is beneficial for proton uptake and catalytic activity but detrimental for electronic conductivity and chemical stability. Figure 1

Experimental assessment of drilling-induced damage in impacted composite laminates for resin-injection repair: Influence of open/blind hole-hole interaction and orientation

An experimental study of drilling-induced damage in barely visible impact damaged (BVID) carbon fibre reinforced polymer (CFRP) laminates where small circular holes were intentionally drilled into the impacted zone as an intermediate step of the resin-injection repair process was described. In-plane compression testing was conducted to determine the mechanical properties of BVID specimens containing open/blind, single and binary holes. Binary-hole specimens at fixed distance apart were tested in parallel or normal to the applied uniaxial force. As expected, BVID specimens experienced significant diminution of property value (compared to pristine ones). No dependence of mechanical properties on hole-hole orientation was observed. Owing to the large hole-hole separation, this significantly mitigated the hole-hole interactions, even though the predicted stress concentration (around the holes) level was above the residual strength. Interestingly, single/binary-hole BVID laminates generated counter-intuitive laminate stiffening effects that the stiffness was significantly higher than that of undrilled BVID specimens.

New signatures of the spin gap in quantum point contacts

One dimensional semiconductor systems with strong spin-orbit interaction are both of fundamental interest and have potential applications to topological quantum computing. Applying a magnetic field can open a spin gap, a pre-requisite for Majorana zero modes. The spin gap is predicted to manifest as a field dependent dip on the first 1D conductance plateau. However, disorder and interaction effects make identifying spin gap signatures challenging. Here we study experimentally and numerically the 1D channel in a series of low disorder p-type GaAs quantum point contacts, where spin-orbit and hole-hole interactions are strong. We demonstrate an alternative signature for probing spin gaps, which is insensitive to disorder, based on the linear and non-linear response to the orientation of the applied magnetic field, and extract a spin-orbit gap ΔE ≈ 500 μeV. This approach could enable one-dimensional hole systems to be developed as a scalable and reproducible platform for topological quantum applications.

Effective Correlation of Two Holes in a Semimagnetic Quantum Well Wire: Influence of Shape of Confining Potential on Coulomb Interaction**Supported by University Grants Commission, New Delhi, India under Major Research Project F. No. 42-816/2013(SR)

The hole-hole interaction has been considered in a Semimagnetic Quantum Well Wire (SQWW). The influence of the shape of the confining potential like square well and parabolic well type on the binding energy of an acceptor impurity with two holes and their Coulomb interaction between them has been studied for various impurity locations. Magnetic field has been used as a probe to understand the carrier-carrier correlation in such Quasi 1-Dimensional QWW since it alters the strength of the confining potential tremendously. In order to show the significance of the correlation between the two holes, the calculations have been done with and without including the correlation effect in the ground state wavefunction of the hyderogenic acceptor impurity and the results have been compared. The expectation value of the Hamiltonian, , is minimized variationaly in the effective mass approximation through which has been obtained.

Spectral functions of nuclear matter using self-consistent Green’s function approach based on three-body force

A self-consistent Green’s Function approach is used to study the influence of short-range correlations beyond the mean-field approach of nuclear matter. The ladder equation, including both particle-particle and hole-hole propagation, is solved in nuclear matter for a realistic interaction derived from the CD-Bonn potential. The hole-hole interaction is used to calculate the spectral functions that describe the distribution of holes below Fermi level. The nucleon spectral functions are calculated from the momentum- and energy-dependent self-energy. For comparison, the calculations are investigated by including nuclear three-body force. These spectral functions directly reflect the effects of the nucleon-nucleon correlations and can be explored by the analysis of nucleon knock-out experiments like $ ({\rm e, e' p})$ .

Ultrafast photoelectron migration in dye-sensitized solar cells: Influence of the binding mode and many-body interactions.

In the present contribution, the ultrafast photoinduced electron migration dynamics at the interface between an alizarin dye and an anatase TiO2 thin film is investigated from first principles. Comparison between a time-dependent many-electron configuration interaction ansatz and a single active electron approach sheds light on the importance of many-body effects, stemming from uniquely defined initial conditions prior to photoexcitation. Particular emphasis is put on understanding the influence of the binding mode on the migration process. The dynamics is analyzed on the basis of a recently introduced toolset in the form of electron yields, electronic fluxes, and flux densities, to reveal microscopic details of the electron migration mechanism. From the many-body perspective, insight into the nature of electron-electron and hole-hole interactions during the charge transfer process is obtained. The present results reveal that the single active electron approach yields quantitatively and phenomenologically similar results as the many-electron ansatz. Furthermore, the charge migration processes in the dye-TiO2 model clusters with different binding modes exhibit similar mechanistic pathways but on largely different time scales.

Optical spectroscopy of single beryllium acceptors in GaAs/AlGaAs quantum well

We carry out microphotoluminescence measurements of an acceptor-bound exciton (${A}^{0}X$) recombination in the applied magnetic field with a single impurity resolution. In order to describe the obtained spectra we develop a theoretical model taking into account a quantum well (QW) confinement, an electron-hole and hole-hole exchange interaction. By means of fitting the measured data with the model we are able to study the fine structure of individual acceptors inside the QW. The good agreement between our experiments and the model indicates that we observe single acceptors in a pure two-dimensional environment whose states are unstrained in the QW plain.

Switching between attractive and repulsive Coulomb-interaction-mediated drag in an ambipolar GaAs/AlGaAs bilayer device

We present measurements of Coulomb drag in an ambipolar GaAs/AlGaAs double quantum well structure that can be configured as both an electron-hole bilayer and a hole-hole bilayer, with an insulating barrier of only 10 nm between the two quantum wells. Coulomb drag resistivity is a direct measure of the strength of interlayer particle-particle interactions. We explore the strongly interacting regime of low carrier densities (2D interaction parameter rs up to 14). Our ambipolar device design allows a comparison between the effects of the attractive electron-hole and repulsive hole-hole interactions and also shows the effects of the different effective masses of electrons and holes in GaAs.

Mid-infrared photodetectors operating over an extended wavelength range up to 90 K.

We report a wavelength threshold extension, from the designed value of 3.1 to 8.9μm, in a p-type heterostructure photodetector. This is associated with the use of a graded barrier and barrier offset, and arises from hole-hole interactions in the detector absorber. Experiments show that using long-pass filters to tune the energies of incident photons gives rise to changes in the intensity of the response. This demonstrates an alternative approach to achieving tuning of the photodetector response without the need to adjust the characteristic energy that is determined by the band structure.

Molecular Excitation Energies from Time-Dependent Density Functional Theory Employing Random-Phase Approximation Hessians with Exact Exchange.

Molecular excitation energies have been calculated with time-dependent density-functional theory (TDDFT) using random-phase approximation Hessians augmented with exact exchange contributions in various orders. It has been observed that this approach yields fairly accurate local valence excitations if combined with accurate asymptotically corrected exchange-correlation potentials used in the ground-state Kohn-Sham calculations. The inclusion of long-range particle-particle with hole-hole interactions in the kernel leads to errors of 0.14 eV only for the lowest excitations of a selection of three alkene, three carbonyl, and five azabenzene molecules, thus surpassing the accuracy of a number of common TDDFT and even some wave function correlation methods. In the case of long-range charge-transfer excitations, the method typically underestimates accurate reference excitation energies by 8% on average, which is better than with standard hybrid-GGA functionals but worse compared to range-separated functional approximations.

Magnetic field spectral crossings of Luttinger holes in quantum wells

We develop an analytic approach to two-dimensional (2D) holes in a magnetic field that allows us to gain insight into physics of measuring the parameters of holes, such as cyclotron resonance, Shubnikov-de Haas effect and spin resonance. We derive hole energies, cyclotron masses, and the $g$ factors in the semiclassical regime analytically, as well as analyze numerical results outside the semiclassical range of parameters, qualitatively explaining the experimentally observed magnetic field dependence of the cyclotron mass. In the semiclassical regime with large Landau level indices, and for size quantization energy much bigger than the cyclotron energy, the cyclotron mass coincides with the in-plane effective mass, calculated in the absence of a magnetic field. The hole $g$ factor in a magnetic field perpendicular to the 2D plane is defined not only by the constant of direct coupling of the angular momentum of the holes to the magnetic field, but also by the Luttinger constants defining the effective masses of holes. We find that the $g$ factor for quasi-2D holes with heavy mass in the [001] growth direction in GaAs quantum well is $g=4.05$ in the semiclasssical regime. Outside the semiclassical range of parameters, holes behave as a species completely different from electrons. Spectra for size- and magnetic-field-quantized holes are nonequidistant, not fanlike, and exhibit multiple crossings, including crossing in the ground level. We calculate the effect of Dresselhaus terms, which transform some of the crossings into anticrossings, and the effects of the anisotropy of the Luttinger Hamiltonian on the 2D hole spectra. Dresselhaus terms of different symmetries are taken into account, and a regularization procedure is developed for the ${k}_{z}^{3}$ Dresselhaus terms. Control of the nonequidistant levels and crossing structure by the magnetic field can be used to control the Landau level mixing in hole systems, and thereby control hole-hole interactions in the magnetic field.

Aglycosylated knob and hole Fc homodimers are anti-parallel

Bispecific antibody and antibody-like molecules are of wide interest as potential therapeutics that can recognize two distinct targets. Among the variety of ways such molecules have been engineered is by creating ""knob"" and ""hole"" heterodimerization sites in the CH3 domains of two antibody heavy chains. The molecules produced in this manner maintain their biological activities while differing very little from the native human IgG sequence. To better understand the knob-into-hole interface, the molecular mechanism of heterodimerization, and to engineer Fc domains that could improve the assembly and purity of bispecific antibodies, we sought crystal structures of heterodimeric and homodimeric aglycosylated Fc fragments bearing ""knob"" and ""hole"" mutations. The structure of the knob-into-hole Fc was determined at 2.64Å. Except for the sites of mutation, the structure is very similar to that of the native human IgG1 Fc, consistent with a hetero-dimer interaction kinetic KD <1 nM. Homodimers of the ""knob"" and ""hole"" mutants were also obtained and their X-ray structures were determined at resolutions of 2.5Å and 2.1Å, respectively. Both kinds of homodimers adopt a head-to-tail quaternary structure and thus do not contain direct knob-knob or hole-hole CH3 interactions. By adding site-directed mutations at F241 and F243 in the CH2 domains, the head-to-tail arrangement was disfavored, leading to increases in both the rate and efficiency of bispecific (heterodimer) assembly.

Role of Many Body Shake-Up in Core-Valence-Valence Electron Emission from Single Wall Carbon Nanotubes

Auger core-valence-valence transitions from single wall Carbon nanotubes are studied using a tight-binding calculational scheme with nearest neighbor overlap, hopping interactions, and a double-zeta basis set. The resulting Hamiltonian approximates the unperturbed pi and sigma bands of the nanomaterials coupled with the free electron states outside the solid and the core-hole. As a first step, the Fermi's golden rule is applied to determine the so called one-electron spectrum of emitted electrons from different tubes, in which either the neutralizing or the ejected electrons, in the initial state, lie within nearest neighboring atomic sites to the core-hole. Many-body corrections are effectively modeled using a broadening function, which accounts for dynamic screening effects involving the initial and final states. Particular attention is paid to the asymmetric component of the broadening function, responsible for the shake-up of pi electrons. Finally, the Cini-Sawatzky distortion function is used to describe the final state effect of the hole-hole interaction. A quantitative estimation of the interplay of shake-up processes is proposed by adjusting the asymmetric parameters of the broadening function to reproduce measurements of Auger electrons ejected from bundles of single wall Carbon nanotubes.

High Fidelity Nano-Hole Enhanced Raman Spectroscopy.

Surface Enhanced Raman Spectroscopy (SERS) is a sensitive technique that can even detect single molecules. However, in many SERS applications, the strongly inhomogeneous distribution of intense local fields makes it very difficult for a quantitive assessment of the fidelity, or reproducibility of the signal, which limits the application of SERS. Herein we report the development of exceptionally high fidelity Hole-Enhanced Raman Spectroscopy (HERS) from ordered, two-dimensional hexagonal nanohole arrays. We take the fidelity f to be a measure of the percent deviation of the Raman peaks from measurement to measurement. Overall, area averaged fidelities for 12 gold array samples ranged from f ~ 2% - 15% for HERS using aqueous R6G molecules. Furthermore, intensity modulations of the enhanced Raman spectra were measured for the first time as a function of polarization angle. The best of these measurements, which focus on static laser spots on the sample, could be consistent with even higher fidelities than the area-averaged results. Nanohole arrays in silver provided supporting polarization measurements and a more complete enhanced Raman fingerprint for phenylalanine molecules. We also carried out finite-difference time-domain calculations to assist in the interpretation of the experiments, identifying the polarization dependence as possibly arising from hole-hole interactions. Our results represent a step towards making quantitative and reproducible enhanced Raman measurements possible and also open new avenues for a large scale source of highly uniform hot spots.

Hole-hole and electron-hole exchange interactions in single InAs/GaAs quantum dots

A combined analysis of microphotoluminescence ($\ensuremath{\mu}\text{PL}$) and microphotoluminescence excitation ($\ensuremath{\mu}\text{PLE}$) spectra of the same single quantum dot (QD) enables an unambiguous identification of four sharp resonances in the excitation spectrum detected on the positive trion transition $({h}_{0}\ensuremath{\rightarrow}{e}_{0}{h}_{0}{h}_{1})$ and reveals the complete fine structure of the hot trion. Transitions into states normally forbidden by (spin) selection rules for optical transitions between pure spin states are observed. The splittings of all triplet states are found to be large (up to 3 meV), asymmetric, and QD size and shape dependent. The experimental data are in excellent agreement with theoretical calculations in the framework of eight-band $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ theory and the configuration-interaction method. To account for the physical effects which lead to the observed fine-structure splitting, parts of the complex model are successively omitted. This approach identifies the anisotropic hole-hole exchange interaction as well as correlation effects dominating the observed fine-structure splitting of the hot trion.