Nonzero Gap Research Articles

Insights of the Proton Transport Efficiency of a Membrane Electrode Assembly by Operando Monitoring of the Local Proton Concentration during Water Oxidation.

Direct estimation of the reaction environment, e.g., local pH at the anode side of a membrane electrode assembly (MEA) of zero gap electrolyzer, is essential to understand possible key factors, which are influencing the sustainable operation of industrial electrolyzers. Herein, we demonstrate a scanning electrochemical microscopy-based strategy to measure the local pH in the close vicinity of an operating MEA. Local proton concentration changes during the oxygen evolution reaction were monitored in the nonzero gap electrolyzer and MEA systems. The measurements constitute a methodology to evaluate the ion transport efficiency of the MEA. The strategy was extended to investigate the effect of an activation process, buffering of the electrolyte, and poisoning effect on the change in proton transport efficiency. This novel strategy enables the estimation of the actual pH of the MEA system during operation and is of great relevance in understanding the process conditions during sustainable fuel production.

Effective quantum gravitational collapse in a polymer framework

We study how the presence of an area gap, different than zero, affects the gravitational collapse of a dust ball. The implementation of such discreteness is achieved through the framework of polymer quantization, a scheme inspired by loop quantum gravity (LQG). We study the collapse using variables which represent the area, in order to impose the non-zero area gap condition. The collapse is analyzed for both the flat and spherical Oppenheimer-Snyder models. In both scenarios the formation of the singularity is avoided, due to the inversion of the velocity at finite values of the sphere surface. This happens due to the presence of a negative pressure, with origins at a quantum level. When the inversion happens inside the black hole event horizon, we achieve a geometry transition to a white hole. When the inversion happens outside the event horizon, we find a new possible astrophysical object. A characterization of such hypothetical object is done. Some constraints on the value for the area gap are also imposed in order to maintain the link with our already established physical theories.

Closing duality gaps of SDPs completely through perturbation when singularity degree is one

Let ( P , D ) be a primal-dual pair of SDPs with a nonzero finite duality gap. Under such circumstances, P and D are weakly feasible and if we perturb the problem data to recover strong feasibility, the (common) optimal value function v as a function of the perturbation is not well-defined at zero (i.e. at the unperturbed data). Nevertheless, under the assumption that both P and D have singularity degree one, we show that a limiting version v a of v is a well-defined monotone decreasing continuous bijective function with domain [ 0 , π / 2 ] and image [ v ( P ) , v ( D ) ] , where v ( P ) and v ( D ) are the optimal values of P and D , respectively. The domain [ 0 , π / 2 ] corresponds to directions of perturbation defined in a certain manner. Thus, v a ‘completely fills’ the nonzero duality gap under a mild regularity condition. Our result is tight in that there exists an instance with singularity degree two for which v a is not continuous.

Control of spin on structural stability, mechanical, magneto-optoelectronic and thermodynamic properties of RbTaX (X =P and As) materials: Emerging candidates for opto-spintronics and spin filter applications

In the present work, the density functional theory has been utilised in inspecting the ground state-structural, electronic, magnetic, optical, elastic and thermodynamic properties of new semiconductor RbTaX (X = P and As) half-Heuslers. Out of the possible three structures (α, β, γ) studied in ferromagnetic (FM) as well as non-magnetic (NM) phases, α – FM phase is found to be the most stable configuration. Both studied materials have estimated a net magnetic moment of 3μB, following the Slater-Pauling rule (Mtot=Ztot−8). With the use of modified Becke Johnson potential (mBJ) potential, the band profile reveals non-zero band gap in the spins and henceforth display spin filter property in the compounds. The predicted energy band gaps for RbTaP and RbTaAs are 3.04 and 2.87 eV for minority spin channels and 0.137 and 0.26 eV for majority spin channels, respectively. This unique feature of the Heusler compound may be advantageous for quantum information processing and spin-transport in electronic and magnetic devices. Also, a moderate exchange splitting and a Curie temperature well above the room temperature are noted. The stability of the materials under investigation was further confirmed by calculations of cohesive energy, formation energy, and second order elastic constants. The optoelectronic as well as thermodynamic properties of the studied compounds are also investigated. The estimated high value of refractive index (>4) is making them suitable for optical lenses. Moreover, photon energy absorption in the visible and ultraviolet spectrums renders them valuable for UV-VIS absorbers.

Singular and Nonsingular Transitions in the Infrared Plasmons of Nearly Touching Nanocube Dimers.

Narrow gaps between plasmon-supporting materials can confine infrared electromagnetic energy at the nanoscale, thus enabling applications in areas such as optical sensing. However, in nanoparticle dimers, the nature of the transition between touching (zero gap) and nearly nontouching (nonzero gap ≲15 nm) regimes is still a subject of debate. Here, we observe both singular and nonsingular transitions in infrared plasmons confined to dimers of fluorine-doped indium oxide nanocubes when moving from touching to nontouching configurations depending on the dimensionality of the contact region. Through spatially resolved electron energy-loss spectroscopy, we find a continuous spectral evolution of the lowest-order plasmon mode across the transition for finite touching areas, in excellent agreement with the simulations. This behavior challenges the widely accepted idea that a singular transition always emerges in the near-touching regime of plasmonic particle dimers. The apparent contradiction is resolved by theoretically examining different types of gap morphologies, revealing that the presence of a finite touching area renders the transition nonsingular, while one-dimensional and point-like contacts produce a singular behavior in which the lowest-order dipolar mode in the touching configuration, characterized by a net induced charge in each of the particles, becomes unphysical as soon as they are separated. Our results provide valuable insights into the nature of dimer plasmons in highly doped semiconductors.

Engineering multiform quantum state transfers and topological devices in a splicing Su–Schrieffer–Heeger chain

We propose to implement the various kinds of topological quantum state transfers (QSTs) in a splicing Su–Schrieffer–Heeger (SSH) chain, where the transfer forms vary with the introduction of the on-site potential and are distinguished by different output ports. The splicing SSH chain without the on-site potential shows an interface symmetry in chain configuration and supports a zero-energy gap state to realize a symmetric state transfer from the central site to the two ends with equal probabilities. After introducing the on-site potential on one end or two ends, we further obtain two asymmetric versions of the splicing SSH chain. The existence of the on-site potential leads to the transformation of the zero-energy gap state into a nonzero gap state, and the nonzero gap state exhibits different distribution characteristics in two asymmetric versions. Accordingly, three QST channels with different forms in a splicing SSH chain are designed, each of which possesses the robustness against the disorder of the couplings and the inaccuracy of the evolution time. In addition, we demonstrate the scalability of a multiform QST protocol with high fidelity. The protocol with different transfer forms is expected to realize diverse functional quantum devices, which effectively improves the utilization of a splicing SSH chain and economizes the physical resource.

Lightcone Modular Bootstrap and Tauberian Theory: A Cardy-Like Formula for Near-Extremal Black Holes

AbstractWe show that for a unitary modular invariant 2D CFT with central charge $$c>1$$ c > 1 and having a nonzero twist gap in the spectrum of Virasoro primaries, for sufficiently large spin J, there always exist spin-J operators with twist falling in the interval $$(\frac{c-1}{12}-\varepsilon ,\frac{c-1}{12}+\varepsilon )$$ ( c - 1 12 - ε , c - 1 12 + ε ) with $$\varepsilon =O(J^{-1/2}\log J)$$ ε = O ( J - 1 / 2 log J ) . We establish that the number of Virasoro primary operators in such a window has a Cardy-like, i.e., $$\exp \left( 2\pi \sqrt{\frac{(c-1)J}{6}}\right) $$ exp 2 π ( c - 1 ) J 6 growth. A similar result is proven for a family of holographic CFTs with the twist gap growing linearly in c and a uniform boundedness condition, in the regime $$J\gg c^3\gg 1$$ J ≫ c 3 ≫ 1 . From the perspective of near-extremal rotating BTZ black holes (without electric charge), our result is valid when the Hawking temperature is much lower than the “gap temperature.”

Multiscale functionalized graphene origami metamaterials enable programming thermoelectric performance of flexible energy harvesters

Origami engineering stands out as one of the prominent approaches for fine tuning the multiphysical properties of energy materials. Employing first-principle calculations at the nanoscale, we explore the mechano-thermoelectric properties of graphene origami metamaterials functionalized by hydrogen (H), nitrogen (N), oxygen (O), and fluorine (F) adatoms. Our computational results reveal that functionalizing carbon (C) atoms induce buckling in the pristine graphene, transitioning carbon atoms from sp2 (for pristine graphene sheet) to hybridized sp3 orbital to fold the graphene origami. The functionalized graphene origami metamaterials, adopting the Miura-ori architecture, exhibit anisotropic mechanical properties and an unprecedented negative Poisson's ratio (NPR) of up to −0.8. Non-symmetrical functionalization breaks the inherent symmetry of graphene, resulting in a robust non-zero electronic band gap. This characteristic makes the graphene origami metamaterial a compelling contender for thermoelectric applications, since they offer an electronic figure of merit that exceed 200 at room temperature (Graphene-H), surpassing that of the majority of 2D thermoelectric materials can offer. Resorting to the finite element approach, we explore the origami-based thermoelectric legs in nanogenerators at mesoscale. The folding capability of origami architectures offer tunable heat insulation in order to realize next generation of thermoelectric legs. Compared to conventional cuboid leg thermoelectric nanogenerators, thermoelectric conversion efficiency of origami metamaterials can be two orders of magnitude higher; an enhancement that is significantly governed by their folding angle. The underlying principles governing the multiphysics performance of multiscale origami-based thermoelectric materials impart novel design concepts for customizing the thermoelectric performance of shape-changing low-dimensional metamaterials and energy-related devices.

Graphitic Carbon Nitride Quantum Dots (g-C3N4 QDs): From Chemistry to Applications.

Since their emergence in 2014, graphitic carbon nitride quantum dots (g-C3N4 QDs) have attracted much interest from the scientific community due to their distinctive physicochemical features, including structural, morphological, electrochemical, and optoelectronic properties. Owing to their desirable characteristics, such as non-zero band gap, ability to be chemically functionalized or doped, possessing tunable properties, outstanding dispersibility in different media, and biocompatibility, g-C3N4 QDs have shown promise for photocatalysis, energy devices, sensing, bioimaging, solar cells, optoelectronics, among other applications. As these fields are rapidly evolving, it is very strenuous to pinpoint the emerging challenges of the g-C3N4 QDs development and application during the last decade, mainly due to the lack of critical reviews of the innovations in the g-C3N4 QDs synthesis pathways and domains of application. Herein, an extensive survey is conducted on the g-C3N4 QDs synthesis, characterization, and applications. Scenarios for the future development of g-C3N4 QDs and their potential applications are highlighted and discussed in detail. The provided critical section suggests a myriad of opportunities for g-C3N4 QDs, especially for their synthesis and functionalization, where a combination of eco-friendly/single step synthesis and chemical modification may be used to prepare g-C3N4 QDs with, for example, enhanced photoluminescence and production yields.

Investigating impact of zinc vapor jet on keyhole dynamics and liquid ejection from molten pool during remote laser welding of zinc-coated steel in zero-gap lap joint configuration

When Zn-coated steels are laser welded in a zero part-to-part gap lap joint configuration, highly pressurised Zn vapors are readily produced, generating spatters in the weld. The best practice is to set a non-zero gap to facilitate vapor degassing; however, this necessitates additional operations, escalating production costs. This paper aims to investigate the keyhole dynamics and the ejections from the molten pool due to the interaction between high-pressure Zn vapors and the liquid metal, during remote laser welding of Zn-coated DX57D+Z steel sheets at zero nominal part-to-part gap in lap joint configuration. This is achieved by complementing experimental trials with multi-physics Computational Fluid Dynamics (CFD) simulations. The findings showed that the interplay between heat-affected zone, Zn evaporation zone, size/shape of the laser beam are critical factors for controlling the effect of Zn vapors jet on keyhole stability and liquid ejections. Opportunities for laser beam shaping are discussed throughout the paper.

Monodisperse Molecular Models for the sp Carbon Allotrope Carbyne; Syntheses, Structures, and Properties of Diplatinum Polyynediyl Complexes with PtC20Pt to PtC52Pt Linkages.

Extended conjugated polyynes provide models for the elusive sp carbon polymer carbyne, but progress has been hampered by numerous synthetic challenges. Stabilities appear to be enhanced by bulky, electropositive transition-metal endgroups. Reactions of trans-(C6F5)(p-tol3P)2Pt(C≡C)nSiEt3 (n = 4-6, PtCxSi (x = 2n)) with n-Bu4N+F-/Me3SiCl followed by excess tetrayne H(C≡C)4SiEt3 (HC8Si) and then CuCl/TMEDA and O2 give the heterocoupling products PtCx+8Si, PtCx+16Si, and sometimes higher homologues. The PtCx+16Si species presumably arise via protodesilylation of PtCx+8Si under the reaction conditions. Chromatography allows the separation of PtC16Si, PtC24Si, and PtC32Si (from n = 4), PtC18Si and PtC26Si (n = 5), or PtC20Si and PtC28Si (n = 6). These and previously reported species are applied in similar oxidative homocouplings, affording the family of diplatinum polyynediyl complexes PtCxPt (x = 20, 24, 28, 32, 36, 40 in 96-34% yields and x = 44, 48, 52 in 22-7% yields). These are carefully characterized by 13C NMR, UV-visible, and Raman spectroscopy and other techniques, with particular attention to behavior as the Cx chain approaches the macromolecular limit and endgroup effects diminish. The crystal structures of solvates of PtC20Pt, PtC24Pt, and PtC26Si, which feature the longest sp chains structurally characterized to date, are analyzed in detail. All data support a polyyne electronic structure with a nonzero optical band gap and bond length alternation for carbyne.

Two-step relaxation in local many-body Floquet systems

We want to understand how relaxation process from an initial non-generic state proceeds towards a long-time typical state reached under unitary quantum evolution. One would expect that after some initial correlation time relaxation will be a simple exponential decay with constant decay rate. We show that this is not necessarily the case. Studying various Floquet systems with fixed two-qubit gates, and focusing on purity and out-of-time-ordered correlation functions, we find that in many situations relaxation proceeds in two phases of exponential decay having different relaxation rates. Namely, in the thermodynamic limit the relaxation rate exhibits a change at a critical time proportional to system’s size. The initial thermodynamically relevant rate can be slower or faster than the asymptotic one, demonstrating that the recently discovered phantom relaxation, in which the decay is slower than predicted by a nonzero transfer matrix gap, is not limited to only random circuits.

Topological phase transition in the antiferromagnetic topological insulator MnBi_2Te_4 from the point of view of axion-like state realization

This work aims to study the conditions of topological phase transition (TPT) between the topological and trivial states in the antiferromagnetic topological insulator (AFM TI) MnBi_2Te_4 and propose some theory about the relationship of this TPT with the possibility of axion-like state realization in this material. Using the density functional approach we have analyzed the changes in the electronic and spin structure of topological surface states (TSSs) and the nearest conduction and valence bands (CB and VB) including the changes in the bulk band gap as well as the Dirac point (DP) gap in TSSs under variation of the spin-orbit coupling strength in the region of the TPT for infinite crystal and slab with a surface both. We have shown that in both cases the TPT occurs with inversion of the contributions of the Bi-p_z and Te-p_z states of different parity at the gap edges related to change in the gap sign. In the case of surface calculations, the Bi-p_z and Te-p_z states at the edges of the bulk band gap and their inversion at the TPT point are transformed into the TSSs with an energy gap at the DP. In this case the TPT takes place without closing the band gap, i.e. with a “jump” through zero and the formation of the nonzero gap during such a transition. Our calculations show that the TPT point is also characterized by an inversion of the out-of-plane spin polarization s_z at the Gamma point for lower and upper parts of the Dirac cone and a significant spatial redistribution of the TSSs between the surface and the bulk. We suppose that the nonzero Dirac gap can have some relationship with the formation of the axion-like state, which presumably couples nonmagnetic spin-orbit and magnetic contributions at the boundary between the topological and trivial phases for a system with parameters close to the TPT conditions. A practically realized system is proposed - the AFM TI with a stoichiometry close to that of MnBi_2Te_2Se_2 with partial (about 50%) substitution of Te atoms for Se atoms in MnBi_2Te_4 which can be an experimental platform for the implementation and experimental analysis of the TPT and the corresponding possibility of the axion-like state realization in Condensed Matter. Besides, such system could serve as a good platform for studying the dynamic axion effect, where the axion field fluctuations are maximised when a small external field is applied to the system which state is close to the TPT.

Accelerating Distributed Optimization via Over-the-Air Computing

Distributed optimization is ubiquitous in emerging applications, such as robust sensor network control, smart grid management, machine learning, resource slicing, and localization. However, the extensive data exchange among local and central nodes may cause a severe communication bottleneck. To overcome this challenge, over-the-air computing (AirComp) is a promising medium access technology, which exploits the superposition property of the wireless multiple access channel (MAC) and offers significant bandwidth savings. In this work, we propose an AirComp framework for general distributed convex optimization problems. Specifically, a distributed primal-dual (DPD) subgradient method is utilized for the optimization procedure. Under general assumptions, we prove that DPD-AirComp can asymptotically achieve zero expected constraint violation. Therefore, DPD-AirComp ensures the feasibility of the original problem, despite the presence of channel fading and additive noise. Moreover, with proper power control of the users’ signals, the expected non-zero optimality gap can also be mitigated. Two practical applications of the proposed framework are presented, namely, smart grid management and wireless resource allocation. Finally, numerical results confirm DPD-AirComp’s excellent performance, while it is also shown that DPD-AirComp converges an order of magnitude faster compared to two digital orthogonal multiple access schemes, specifically, time-division multiple access (TDMA), and orthogonal frequency-division multiple access (OFDMA).

Ab-initio investigation of the fundamental properties of metals (X = Be, Mg, and Ca) encapsulated CsXO3 tin-based perovskite materials

Perovskite material are widely used in Solar cell device due to it promising properties and power conversion efficiencies (PCE). Most importantly, properties of the absorber layer such as the band gap, electronic, optical, chemical composition and the grain size of the perovskite absorbed layer are very sacrosanct when determining efficacy of the material for such application. Thus, in this work, the optical, structural stability, electronic, and mechanical properties of non-halide cubic perovskite CsXO3 (X = Mg, Be and Ca) was extensively studied using the first principles Density functional theory (DFT) approach. The structural, electronic and optoelectronic properties was evaluated using Quantum Espresso Simulation Package (QESP) with the plane wave self-consistent field (PWscf) code. The structural computation reveals that the Lattice constant as well as total energy of CsXO3 (X = Be, Mg and Ca) increases as the size of cation X (X = Be, Mg and Ca) increases such that CsCaO3 possess the highest energy. Contrary, the fermi energy decreases with increase in cationic size, however, CsCaO3 has the highest lattice constant value 4.3743 eV. Electronic properties investigation shows that the studied perovskite has a metallic property with no forbidden band. zero band gap materials can adsorb photon across the entire solar spectrum, including lower-energy photons which is an advantage over a non-zero band gap which can only absorb photon with energies higher than the band gap energy can be absorbed and converted into electricity. This enables more efficient utilization of sunlight and increased overall energy conversion. To ascertain the effect of atomic exchange and orbital contribution in the formation of electronic properties, partial density of state (PDOS) was calculated and the result reveal that electron transition occurs mostly from p-orbital oxygen atom having major contribution on the valence band to the d-orbital of Caesium atom having major contribution on the conduction band and X-cation having minor contribution. CsXO3 (X = Be, Mg and Ca) also shows fascinating optical properties and thus can be used to improve solar cell device.

Natural overlaying behaviors push the limit of planar cyclic deformation performance in few‐layer MoS2 nanosheets

AbstractAs a typical two‐dimensional (2D) transition metal dichalcogenides (TMDCs) material with nonzero band gap, MoS2 has a wide range of potential applications as building blocks in the field of nanoelectronics. The stability and reliability of the corresponding nanoelectronic devices depend critically on the mechanical performance and cyclic reliability of 2D MoS2. Although an in situ technique has been used to analyze the mechanical properties of 2D materials, the cyclic mechanical behavior, that is, fatigue, remains a major challenge in the practical application of the devices. This study was aimed at analyzing the planar cyclic performance and deformation behavior of three‐layer MoS2 nanosheets (NSs) using an in situ transmission electron microscopy (TEM) variable‐amplitude uniaxial low‐frequency and cyclic loading–unloading tensile acceleration test. We also elucidated the strengthening effect of the natural overlaying affix fragments (other external NSs) or wrinkle folds (internal folds from the NS itself) on cycling performances and service life of MoS2 NSs by delaying the whole process of fatigue crack initiation, propagation, and fracture. The results have been confirmed by molecular dynamics (MDs) simulations. The overlaying enhancement effect effectively ensures the long‐term reliability and stability of nanoelectronic devices made of few‐layer 2D materials.image

Effect of Hydrogen concentration on the structural, electronic and optical properties of 2D monolayer MXenes: DFT study

After the discovery of graphene and its unique optical properties, the investigation and discovery of 2D materials expanded. Electrons and phonons of 2D materials react differently to light compared to their bulk state, which will cause unique optical properties. Compared to graphene, 2D monolayer MXenes have non-zero gap energy, which increases their application in optical industries. In this article the density-functional-theory (DFT) approach is employed to investigate the electronic, structural and optical properties of (M2CO2, M = Zr, Sc, Mo and Hf) 2D monolayer MXenes. On the other hand, with the addition of Hydrogen to MXenes (M2C(OH)2), their structural and optical properties change significantly. The electronic band structure results showed that Zr2CO2, Sc2CO2 and Hf2CO2 monolayers are semiconductors with indirect band gaps and Mo2CO2 is a conductor. By adding hydrogen to the layers, Sc2CO2 monolayers changed from an indirect band gap semiconductor to a direct band gap semiconductor. The optical results showed that the highest static refractive index belongs to Zr2CO2 monolayers and the lowest to Sc2CO2. By adding hydrogen to the system, the refractive index of Sc2C(OH)2 increases. According to the imaginary part of the dielectric function, the optical gap of Sc2CO2 has the highest value. Also, Mo2CO2 monolayers does not have an optical gap. These results are in agreement with the electronic band structure results.

Evaluation of DFT+U and HSE Frameworks for Strongly Correlated Iron Oxide

AbstractFor strongly correlated metal oxides, several density functional theories have been used to describe the electronic structure of bulk iron oxide (α‐Fe2O3) and corresponding surfaces, including GGA+U and hybrid functionals (HSE), but the accuracy of these methods is unclear for these metal oxides. In the present study, first‐principles simulations were carried out to examine the effects of a hybrid density functional on α‐Fe2O3 bulk and surface slabs. Further, by using GGA+U, van der Waals corrections and O2 over binding corrections were also examined. It has been found that HSE functionals with 17.5 % Fock exchange predict better properties than those with 12 % or 25 % exchange. Methodological studies indicate that GGA+U predicted zero‐bandgap surface slabs become semiconducting slabs at HSE, and that calculated bandgaps are dependent on the actual exchange addition percentage. Our studies also show that the surface energy and relative stability of different Fe2O3 terminations are less sensitive to the inclusion of dispersion terms. However, when accounting for the GGA‐error in O2 over‐binding, significant changes occur in the computed surface energies. Additionally, HSE06 functional was tested on MnO2(0001) and MnO2(110) surfaces. Both surfaces were identified as metallic by a PBE+U calculation, and an HSE06 analysis revealed a nonzero band gap.

Interface contact and modulated electronic properties by in-plain strains in a graphene-MoS2 heterostructure.

Designing a specific heterojunction by assembling suitable two-dimensional (2D) semiconductors has shown significant potential in next-generation micro-nano electronic devices. In this paper, we study the structural and electronic properties of graphene-MoS2 (Gr-MoS2) heterostructures with in-plain biaxial strain using density functional theory. It is found that the interaction between graphene and monolayer MoS2 is characterized by a weak van der Waals interlayer coupling with the stable layer spacing of 3.39 Å and binding energy of 0.35 J m-2. In the presence of MoS2, the linear bands on the Dirac cone of graphene are slightly split. A tiny band gap about 1.2 meV opens in the Gr-MoS2 heterojunction due to the breaking of sublattice symmetry, and it could be effectively modulated by strain. Furthermore, an n-type Schottky contact is formed at the Gr-MoS2 interface with a Schottky barrier height of 0.33 eV, which can be effectively modulated by in-plane strain. Especially, an n-type ohmic contact is obtained when 6% tensile strain is imposed. The appearance of the non-zero band gap in graphene has opened up new possibilities for its application and the ohmic contact predicts the Gr-MoS2 van der Waals heterojunction nanocomposite as a competitive candidate in next-generation optoelectronics and Schottky devices.

Gravity-resisting colloidal collectives.

Self-assembly of dynamic colloidal structures along the vertical direction has been challenging because of gravity and the complexity in controlling agent-agent interactions. Here, we present a strategy that enables the self-growing of gravity-resisting colloidal collectives. By designing a unique dual-axis oscillating magnetic field, time-varying interparticle interactions are induced to assemble magnetic particles against gravity into vertical collectives, with the structures continuing to grow until reaching dynamic equilibrium. The collectives have swarm behavior and are capable of height reconfiguration and adaptive locomotion, such as moving along a tilted substrate and under nonzero fluidic flow condition, gap and obstacle crossing, and stair climbing.