Band Calculations Research Articles

Electronic structure of 2(5H)-thiophenone studied by UPS and soft X-ray spectroscopy

Abstract The electronic structure of 2(5H)-thiophenone in the gas phase was investigated by ultraviolet photoelectron spectroscopy (UPS) and x-ray photoemission spectroscopy (XPS) and near edge x-ray absorption fine structure (NEXAFS) spectroscopy at the C 1s, O 1s, and S 2p edges. All assignments of the experimental results are supported by both ab-initio electron propagator OVGF calculations for the valence photoemission bands and density functional theory (DFT) and relativistic time dependent DFT calculations for the core levels XPS and NEXAFS spectra. Overall good agreement between experiment and theory is observed; this is especially true for core electron excitations which has permitted an unambiguous assignment of the observed spectral features in terms of single-particle excitations to virtual molecular orbitals. The assignment of the valence band spectra based on OVGF calculations, although satisfactory, points to the importance of electron correlations effects that partially break the single particle picture of ionization.

Ferromagnetic ferroelectricity due to the Kugel-Khomskii mechanism of orbital ordering assisted by atomic Hund's second rule effects

The exchange interactions in insulators depend on the orbital state of magnetic ions, obeying certain phenomenological principles, known as Goodenough-Kanamori-Anderson rules. Particularly, the ferro order of alike orbitals tends to stabilize antiferromagnetic interactions, while the antiferro order of unlike orbitals favors ferromagnetic interactions. The Kugel-Khomskii theory provides a universal view on such coupling between spin and orbital degrees of freedom, based on the superexchange processes: namely, for a given magnetic order, the occupied orbitals tend to arrange in a way to further minimize the exchange energy. Then, if two magnetic sites are connected by the spatial inversion, the antiferro orbital order should lead to the ferromagnetic coupling break the inversion symmetry. This constitutes the basic idea of our work, which provides a pathway for designing ferromagnetic ferroelectrics: the rare but fundamentally and practically important multiferroic materials. After illustrating the basic idea on toy-model examples, we propose that such behavior can be indeed realized in the van der Waals ferromagnet VI3, employing for this analysis the realistic model derived from first-principles calculations for magnetic 3d bands. We argue that the intra-atomic interactions responsible for Hund's second rule, acting against the crystal field, tend to restore the orbital degeneracy of the ionic d2 state in VI3 and, thus, provide a necessary flexibility for activating the Kugel-Khomskii mechanism of the orbital ordering. In the honeycomb lattice, this orbital ordering breaks the inversion symmetry, stabilizing the ferromagnetic-ferroelectric ground state. The symmetry breaking leads to the canting of magnetization, which can be further controlled by the magnetic field, producing a huge change of electric polarization. Published by the American Physical Society 2024

Revealing the Interplay of Local Environments and Ionic Transport in Perovskite Solid Electrolytes.

Solid-state ionic conduction is significantly influenced by bottleneck sizes, which impede ion diffusion within solid lattices. Using aberration-corrected scanning transmission electron microscopy and multislice electron ptychography, we directly observed that increased La occupancy in the perovskite solid electrolyte Li0.5La0.5TiO3 correlates with reduced bottleneck sizes formed by four oxygen atoms connecting neighboring A-site cages. This correlation was also confirmed in local aperiodic regions, where smaller bottleneck sizes due to increased La occupancies affect the directionality and dimensionality of the Li+ ion conductivity. Furthermore, while prior studies have focused on averaged Li+ ion diffusion across different bottleneck areas or chemical environments, by devising a molecular dynamics (MD)-based methodology, we quantify the diffusivity of Li+ ions through specific bottleneck regions. Atomistic simulations, including nudged elastic band calculations and this MD-based methodology, revealed that larger bottleneck sizes correlate with smaller local migration barriers and higher local diffusivity. This study elucidates the relationship among local chemistry, lattice structure, and Li+ ion transport, providing insights for the design of advanced oxide solid electrolytes.

Influence of oxygen on the hydrogen storage performance of Zr2Fe: Mechanism, diffusion pathway and DFT calculations

Zr2Fe alloy exhibits the advantages of being tritiated water-free and easy to recover in the form of reversible metal hydrides, which make it an ideal material for the trapping of hydrogen isotopes. However, its practical application is significantly limited by its susceptibility to poisoning by impurity gases such as oxygen. While significant progress has been made in understanding the effects of oxygen on hydrogen adsorption, a microscopic-level explanation of this interaction is still lacking. In this work, we employed detailed density functional theory to investigate the microscopic interaction mechanism between O2 and Zr2Fe, as well as the impact on hydrogen adsorption, addressing a gap in the current understanding. Our results reveal that O2 dissociatively adsorbs at hollow sites on the Zr2Fe surface, with oxygen atoms forming strong bonds with Zr and Fe atoms. This interaction blocks key active sites, hindering hydrogen diffusion into the alloy’s interior, as confirmed by climbing-image nudged elastic band calculations. These findings provide new insights into the inhibition mechanism caused by oxygen, offering a deeper understanding for improving the hydrogen storage performance of Zr-based alloys.

Potential-dependent kinetics of oxygen chemisorption as the crucial step of oxygen reduction reaction: GCDFT study

Nitrogen-doped carbon materials (NCMs) are widely regarded as promising alternatives to expensive platinum-based electrocatalysts for the oxygen reduction reaction (ORR). While NCMs exhibit considerable electrochemical activity in alkaline media, their performance in acidic environments remains a significant challenge. However, acidic conditions are commercially desirable for ORR’s catalysis in proton-exchange membrane fuel cells (PEMFCs). The dramatic pH dependence of NCM effectiveness has sparked ongoing debate, with several factors under consideration, including surface protonation, variations in hydrogen binding energy, differences in proton donors, and interface structure. In this work, we present a grand canonical density functional theory (GCDFT) study of the chemisorption step on pristine and nitrogen-doped graphene. Through nudged elastic band (NEB) calculations at various electrode potentials, we propose a potential-dependent (and thus pH-dependent) mechanism of oxygen chemisorption at graphitic nitrogen (Ngr) defects, offering new insights into the pH dependency of the onset potential in NCM catalysts.

Enhanced catalytic activity of modified g-C3N4 heterojunction for photocatalytic degradation of methylene blue from wastewater

Rapid recombination of photoinduced charge carriers and poor photocatalytic degradation performance greatly hinder the large-scale application of g-C3N4 photocatalysis. Therefore, the g-C3N4 is modified by BiPO4 to overcome its poor photocatalytic performance, which is investigated by methylene blue (MB) removal. The S scheme heterojunction is constructed by modifying g-C3N4 with BiPO4, which can effectively preserve the redox activities of holes and electrons on VB and CB, exhibiting good photocatalytic activity. Therefore, the modified g-C3N4 exhibits excellent photocatalytic activity with efficient separation of the photoelectron-hole, compared to pure g-C3N4 and BiPO4. The modified g-C3N4 exhibits large MB degradation removal of 96.7 %, which is significantly larger than the pure g-C3N4 (46.3 %) and BiPO4 (3.3 %) owe to synergy, respectively. The photodegradation rate constant of the modified g-C3N4 is 4.8 and 43 times larger than that of the pure g-C3N4 and BiPO4, respectively. The modified g-C3N4 still has large MB removal of 92.9 % after 5 cycles, indicating excellent stability and recyclability. The fractal density calculation of the modified g-C3N4 is investigated combined with LUMO and HOMO analysis. The MB photocatalytic degradation process follows the S scheme charge transfer mechanism, based on degradation mechanism analysis combined with semiconductor energy band and density functional theory calculation analysis. The MB photocatalytic degradation path is systemically analyzed based on MS-UPLC result analysis, which indicates that MB is finally decomposed into CO2 and H2O, achieving the degradation of MB.

Atomic and electronic structures of the [formula omitted]-FeSi2/Si(001) interface

The atomistic interface structure between β-FeSi2 and Si substrate was investigated by cross-sectional scanning transmission electron microscopy and density functional theory calculations (DFT). A high quality single crystalline β-FeSi2 film was epitaxialy grown on Si(001) substrate. We demonstrate that the β-FeSi2(100) plane is bonded to the Si(001) plane with two Si dimers per unit cell. With such interface structure, DFT band calculations reveal that metallic electronic states are localized at the interface. This finding implies the presence of two dimensional electronic states at the interface of β-FeSi2/Si(001), which may have potential applications in silicon-based electronic devices.

Effect of Electric Fields on the Decomposition of Phosphate Esters.

Phosphate esters decompose on metal surfaces and form protective polyphosphate films. For many applications, such as in lubricants for electric vehicles and wind turbines, an understanding of the effect of electric fields on molecular decomposition is urgently required. Experimental investigations have yielded contradictory results, with some suggesting that electric fields improve tribological performance, while others have reported the opposite effect. Here, we use nonequilibrium molecular dynamics (NEMD) simulations to study the decomposition of tri-n-butyl phosphate (TNBP) molecules nanoconfined between ferrous surfaces (iron and iron oxide) under electrostatic fields. The reactive force field (ReaxFF) method is used to model the effects of chemical bonding and molecular dissociation. We show that the charge transfer with the polarization current equalization (QTPIE) method gives more realistic behavior compared to the standard charge equilibration (QEq) method under applied electrostatic fields. The rate of TNBP decomposition via carbon-oxygen bond dissociation is faster in the nanoconfined systems than that in the bulk due to the catalytic action of the surfaces. In all cases, the application of an electric field accelerates TNBP decomposition. When electric fields are applied to the confined systems, the phosphate anions are pulled toward the surface with high electric potential, while the alkyl cations are pulled to the surface with lower potential, leading to asymmetric film growth. Analysis of the temperature- and electric field strength-dependent dissociation rate constants using the Arrhenius equation suggests that, on reactive iron surfaces, the increased reactivity under an applied electric field is driven mostly by an increase in the pre-exponential factor, which is linked to the number of molecule-surface collisions. Conversely, the accelerated decomposition of TNBP on iron oxide surfaces can be attributed to a reduction in the activation energy with increasing electric field strength. Single-molecule nudged-elastic band (NEB) calculations also show a linear reduction in the energy barrier for carbon-oxygen bond breaking with electric field strength, due to stabilization of the charged transition state. The simulation results are consistent with experimental observations of enhanced and asymmetric tribofilm growth under electrostatic fields.

A highly efficient semi-finishing approach for polycrystalline diamond film via plasma-based anisotropic etching

Plasma anisotropic etching polishing (plasma-AEP), a non-contact polishing method, is proposed to achieve highly efficient planarization of polycrystalline diamond (PCD) films. Inductively coupled plasma, with a high concentration of reactive radicals, serves as the source of plasma-AEP. In-situ observation confirms that the planarization effect of plasma-AEP is realized through the preferential removal of the top areas of the pyramid-shaped protrusions, despite the entire surface being uniformly irradiated by the plasma. The material removal rate in plasma-AEP for PCD achieves 127 μm/min. Plasma-AEP is proven effective for PCD films with thicknesses of 0.5, 1, and 2 mm, demonstrating a generic semi-finishing approach for PCD regardless of thickness. Atomic-scale nudged elastic band calculations revealed that the energy barriers for CO and CO2 desorption from 1- and 2-coordinated C atoms are significantly lower than those for 3- and 4-coordinated ones. ReaxFF molecular dynamics simulations showed that at the top areas of the pyramid-shaped protrusions, 1- and 2-coordinated C atoms with a higher etching priority remained dominant during plasma-AEP, leading to the preferential removal of C atoms forming these protrusions. Furthermore, contact polishing was added to complete the finishing of the PCD film, followed by plasma-AEP, resulting in a nanoscale smooth surface with a roughness of 3.4 nm. Transmission electron microscopy confirmed that the crystal structures on the surface and subsurface of the PCD film were well ordered. Overall, this paper displays that plasma-AEP is a promising approach for highly efficient semi-finishing of PCD films.

Study of native point defects in Al0.5Ga0.5N by first principles calculations

To explore the formation mechanism of native point defects in high Al content AlGaN film, the first principles methods are applied to study the native point defects in Al0.5Ga0.5N. The different kinds of vacancies, interstitials, and antisites are investigated. The formation energies of Al0.5Ga0.5N with native point defects under different charge states and growth conditions are analyzed and compared. Then, the preferable charge state, donor and acceptor properties of Al0.5Ga0.5N with different native point defects are explicitly obtained. The results show that AlN, GaN, Ali, and VN exhibit donor properties in p-type condition while VGa, VAl, VN, and NGa exhibit acceptor properties and can play roles as compensating center in n-type Al0.5Ga0.5N under metal rich condition. For N rich condition,VGa, VAl, NGa, and NAl are favorable acceptors in n-type Al0.5Ga0.5N. Meanwhile, the charge distribution and bonding state of Al0.5Ga0.5N with native point defects are explored. It is found the N atoms in Ni and NGa form covalent bond and ionic bond with atoms in Al0.5Ga0.5N. Moreover, the band calculation reveals that the removal of N atom in Al0.5Ga0.5N makes the conduction band fatter and the effective masses of electrons increase while the introduction of N point defects make the valence band flatter, increasing the effective masses of holes. Furthermore, the corresponding thermodynamic transition energy levels of defects under different charge states are summarized. It is found that the thermodynamic transitions for VN, Ni, and NAl may likely to happen under certain conditions. The above studies yield a detailed and quantitative description of native point defects in Al0.5Ga0.5N, which helps to get a deeper insight to the growth and doping of AlGaN.

Effect of Chemical Doping on Ion Transport in Sulfide Solid Electrolytes

Rechargeable solid-state batteries (SSBs) offer tremendous promise as a safe and energy-dense storage technology for use in electric transportation, robotics, and portable electronics. Lithium argyrodites (e.g., Li7PS6, and its halogen-doped derivatives) have emerged as a lucrative class of solid-state electrolytes (SSEs) for SSBs owing to their high Li-ion conductivity (~10-3 S/cm), good elastic stiffness (~30 GPa), and low flammability. Meanwhile, sulfide-based solid electrolytes such as Na3SbS4 (NSS) also showcase substantial potential for SSBs with their high theoretical specific capacity, enhanced safety, and abundance of resources. Despite their promise, both lithium and sodium-based SSBs remain far from commercialization due to lack of atomic-scale understanding of ion-conduction, charge transport, structural evolution, and interfacial reactions (e.g., dendrite growth, electrolyte decomposition etc.). Here we employ a combination of density functional theory calculations, ab initio molecular dynamics simulations, and nudged elastic band calculations to understand ion transport mechanism in chemically doped lithium argyrodites and NSS.In lithium-based systems, using accurate materials modeling, we design fluorine-containing argyrodite electrolytes that offers enhanced Li-ion conduction facilitated by unique Li-disorder induced by fluorine and other halogen co-dopants. Our results show the opening up of new pathways for Li inter-cage hops in these fluorine -containing argyrodite electrolytes which increases the Li-ion conductivity. In the case of sodium-based systems, we focus on atomic-scale mechanisms underlying Na-ion conduction in the presence of cation dopants. Ab initio molecular dynamics simulations reveal the significant impact of cation dopants on NSS, where the introduction of charge-compensating Na-vacancies enhances Na-ion conduction. The size of the cation dopant is found to be a critical factor, with examples such as Ca-doped NSS (rCa2+ / rNa+ = 0.98) showing a conductivity approximately 10 times that of pristine NSS, while larger Ba2+ as a dopant (rBa2+ / rNa+ = 1.35) hinders Na-ion hops due to local strain, resulting in a Na-ion conductivity ~5 times that of NSS. We will discuss these results in the context of accelerating design of novel solid-state electrolytes for long-lived, stable, and high-energy density SSBs.

Crystal and band structures of N-doped Ti3O5 coatings: Experiments and first-principles calculations

N-doped α-phase Ti3O5 has received limited attention in both theoretical and experimental studies compared to N-doped TiO2. This work focuses on the production and analysis of N-doped Ti3O5 coatings, which can be facilely produced using air-based sputtering. First-principles calculations were employed to investigate the crystal and band structures of N-doped Ti3O5. The results revealed that substitutional nitrogen doping within the investigated range preserved the orthorhombic structure of Ti3O5. As the N-doping concentrations increased, Ti3O5 exhibited a transition from metallic to semiconducting characteristics, confirmed by the density of states and refined band calculations. The calculated bandgaps in the semiconductor regime aligned well with the limited experimental results, demonstrating the pronounced narrowing effect of nitrogen doping. Integrating these calculations with experimental findings enhances the understanding of the crystalline and physical properties of N-doped Ti3O5 coatings.

Molecular beam epitaxy growth and doping modulation of topological semimetal NiTe2

In this study, high-quality thin films of the topological semimetal phase NiTe2 were prepared using the molecular beam epitaxy technique, confirmed through x-ray diffraction with pronounced Laue oscillations. Electrical transport experiments reveal that thick films have properties similar to bulk materials. By employing co-deposition, we introduced either magnetic or non-magnetic elements during the growth of thinner films, significantly altering their electrical properties. Notably, the magnetic element Cr induces long-range ferromagnetic ordering, leading to the observation of a significant anomalous Hall effect in NiTe2 thin films. The Hall conductivity remains nearly constant well below the Curie temperature, indicating the correlation with the intrinsic topological nature of the band structure. Theoretical first principles band calculations support the generation of the Weyl semimetal state in the material through magnetic doping. These findings pave the way for exploring more magnetic Weyl semimetals and related low-dimensional quantum devices based on topological semimetals.

Molecular dissociation of nitric oxide (NO) on VO2(010) surface : A DFT study including vdW forces

The adsorption and coadsorption of O and N atomic species, as well as the dissociation of NO molecule on VO2(010) surface have been studied using the density functional theory (DFT) with GGA-PBE as the exchange–correlation, including van der Waals (vdW) corrections of the form PBE+vdW-DF2. We found that the short-bridge (sb) site is the energetically most stable for both N and O atoms. The inclusion of PBE+vdW-DF2 corrections does not change the preferred adsorption site, however it reduces the value of the adsorption energy relative to ordinary GGA-PBE functional. Also, while the GGA-PBE functional results in finite magnetization on the O and N atoms when adsorbed on the VO2 surface, the inclusion of the vdW forces results in zero magnetization of the atoms. In addition, our Löwdin charge transfer analysis shows electron transfer from the VO2(010) surface to the O atom, which is further supported by an accumulation of charge density around the O atom as well as the charge depletion from the V surface atoms. At a lower coverage θ= 0.25 ML, the N atom behaves like a charge acceptor, that is, electrons are transferred from the VO2 surface to it. At a higher coverage θ= 0.50 ML and 0.75 ML, the N atom behaves like a charge donor, i.e., there is a transfer of electronic charges to the VO2 surface. We emphasize that charge transfer between the adsorbate (O and N) and the surface establishes adsorbate-surface bonding which enhances the stability of the adsorbate. Furthermore, our nudged elastic band calculations (NEB) for determining the minimum energy path (MEP) and activation barrier energy (Ea) for NO dissociation into N and O atoms show Ea= 2.18 eV (1.78 eV) as obtained using the GGA-PBE (PBE+vdW-DF2) functionals. Regarding potential application, this study thus contributes to reducing the amount and harmful effect of NO gas in the atmosphere.

Exploring Ti active sites in Ziegler-Natta catalysts through realistic-scale computer simulations with universal neural network potential

We investigate the interaction dynamics between TiCl4 molecules and a MgCl2 (110) cluster to understand the complexities of Ziegler-Natta catalysts through molecular dynamics simulations. Our study reveals significant distortion of Mg atoms at the edge of cluster, influencing TiCl4 adsorption behavior, cluster stability, and reactivity. Various TiCl4 configurations on the MgCl2 surface, such as octahedral and bridging forms, illustrate the versatility of surface in accommodating different molecular arrangements, affecting catalytic performance. We explore diverse adsorption sites influenced by surface topology and electronic properties, revealing a range of adsorption energies from 15.7 to 29.2 kcal/mol. This indicates a complex interplay of molecular forces, significantly impacting catalytic efficiency at distorted sites. Nudged Elastic Band calculations reveal varied activation energies for ethylene insertion, suggesting faster reaction rates at certain sites and highlighting highly favorable dynamics at Corradini type Ti active sites. All these findings offer new directions for enhancing catalyst performances.

Enabling high throughput deep reinforcement learning with first principles to investigate catalytic reaction mechanisms

Exploring catalytic reaction mechanisms is crucial for understanding chemical processes, optimizing reaction conditions, and developing more effective catalysts. We present a reaction-agnostic framework based on high-throughput deep reinforcement learning with first principles (HDRL-FP) that offers excellent generalizability for investigating catalytic reactions. HDRL-FP introduces a generalizable reinforcement learning representation of catalytic reactions constructed solely from atomic positions, which are subsequently mapped to first-principles-derived potential energy landscapes. By leveraging thousands of simultaneous simulations on a single GPU, HDRL-FP enables rapid convergence to the optimal reaction path at a low cost. Its effectiveness is demonstrated through the studies of hydrogen and nitrogen migration in Haber-Bosch ammonia synthesis on the Fe(111) surface. Our findings reveal that the Langmuir-Hinshelwood mechanism shares the same transition state as the Eley-Rideal mechanism for H migration to NH2, forming ammonia. Furthermore, the reaction path identified herein exhibits a lower energy barrier compared to that through nudged elastic band calculation.

Effects of strain-tunable valleys on charge transport in bismuth

The manipulation of the valley degree of freedom can boost the technological development of novel functional devices based on valleytronics. The current mainstream platform for valleytronics is to produce a monolayer with inversion asymmetry, in which the strain-band engineering through the substrates can serve to improve the performance of valley-based devices. However, pinpointing the effective role of strain is inevitable for the precise design of the desired valley structure. Here, we demonstrate the charge transport under continuously controllable external strain for bulk bismuth crystals with three equivalent electron valleys and one hole valley. The strain response of resistance, namely elastoresistance, exhibits evolutions in both antisymmetric and symmetric channels with decreasing temperature. The elastoresistance behaviors mainly reflect the significant changes in valley density depending on the symmetry of induced strain, evidenced by our strain-dependent quantum oscillation measurements and first-principles band calculations under strain. These facts suggest the successful tuning and evaluation of the valley populations through strain-dependent charge valley transport. Published by the American Physical Society 2024

High molecular oxygen activation capacity of carbon defective g-C3N5 for photocatalytic degradation of antibiotics in water

In this study, a carbon deficient g-C3N5 for photocatalytic degradation of antibiotics in water was prepared by thermal polymerization at 600 °C followed by hydrothermal at 180 °C for 12 h, and named CN600-12. The variation of XRD patterns in the physical phase characterization combined with calculations for energy bands in density functional theory (DFT) presents a method for analyzing defects in g-C3N5. The degradation efficiency of CN600-12 on different antibiotics and dyes reached 90% within 90 min, proving its excellent universal applicability. In addition, the prepared CN600-12 has superior stability and environmental friendliness. The burst experiments and ESR data reflect the high yields of oxygenated reactive groups (·O2– and 1O2). The oxygen adsorption capacity of the materials was calculated by combining DFT, the effect of defect configuration on oxygen adsorption was analyzed, and photoelectrochemical characterization explored their photogenerated carrier separation ability. The results show that introducing carbon defects improves the adsorption capacity of the material for oxygen. At the same time, improving the energy band structure and the separation of photogenerated carriers give the material a strong activation capacity for molecular oxygen. This study provides a feasible reference for solving the problem of antibiotic pollution in water bodies.

Theoretical study of alkali metals (Li, Na, K) intercalation in the H2Ti3O7(1 0 0) surface

The H2Ti3O7 system has potential to be applied as a Li/Na/K-ion battery anode material. It is relevant to theoretically study the (100) nanosheet of this material since there are no studies regarding intercalation of Li/Na/K in it. Density Functional Theory calculations with the Hubbard methodology (DFT + U) were conducted in order to find and test several intercalation sites for the three different metals, finding stability and high voltages in all of them. Moreover, the electronic density of states confirms the stability of the systems and charge transfer studies were performed to compare the electron transfer between the most stable sites of each intercalated metal and the surface. Nudged Elastic Band (NEB) calculations were performed, finding lower barriers of 0.54 eV and 0.41 eV for Li and Na diffusion. This study shows that this material is promising and can be a guide for future works.

180 °-twisted bilayer ReSe2 as an artificial noncentrosymmetric semiconductor

We have fabricated a 180 °-twisted bilayer ReSe2 by stacking two centrosymmetric monolayer ReSe2 flakes in opposite directions, which is expected to cause the loss of spatial inversion symmetry. We successfully observed spatial inversion-symmetry breaking, in contrast to the monolayer and natural bilayer ReSe2 by the second harmonic generation. ARPES measurements further revealed emergent band dispersions in the 180 °-twisted bilayer ReSe2, distinct from those of the monolayer ReSe2 used in its fabrication. The band calculation shows the finite lifting of spin degeneracy (∼50 meV) distinct from natural monolayer and bilayer ReSe2, which demonstrates that the spin-momentum locked state leading to Berry curvature related phenomena can be realized even with the stacking of centrosymmetric monolayers. Published by the American Physical Society 2024