The discovery of novel carbon allotropes—from fullerenes and nanotubes to graphene—has greatly advanced contemporary materials research. Beyond conventional atomic crystals, superatomic solids provide an attractive platform for exploring structure-property relationships arising from their unique hierarchical architectures. Here, using state-of-the-art first-principles calculations, we propose a three-dimensional (3D) diamond-like fullerene (${\mathrm{C}}_{60}$) phase, dubbed fullerdiamond (FLD), constructed by substituting each carbon atom in diamond with a ${\mathrm{C}}_{60}$ superatom, where each ${\mathrm{C}}_{60}$ covalently connects to its four neighbors via four 66/66 [2+2] cycloadditions. Our calculations reveal that FLD is structurally stable, with the lowest density (1.098 $\mathrm{g}/{\mathrm{cm}}^3$) among diamond-type structures and anisotropic Young's moduli of $50.91\sim 85.35$ GPa. Its electronic structure exhibits a sizable indirect band gap of 1.83 eV and two distinctive features: (i) an accidental pseudo-Dirac cone (∼57 meV gap) in the conduction band arising from antibonding coupling between LUMO states of neighboring ${\mathrm{C}}_{60}$ superatoms, and (ii) a narrow flat band (∼104 meV) in the valence band. Moreover, a tensile strain of ∼3% along the [100] direction weakens the antibonding orbital coupling between neighboring ${\mathrm{C}}_{60}$ superatoms through elongation of the inter-cage [2+2] cycloaddition bonds, reducing the accidental pseudo-Dirac gap to ∼4 meV and narrowing the flat band width to ∼88 meV. This strain-tunable electronic behavior—arising from the sensitivity of inter-${\mathrm{C}}_{60}$ orbital coupling to lattice deformation—establishes a conceptual bridge between fullerene molecular physics and diamond-like 3D superatomic solid physics. Our findings highlight FLD as a promising platform for tuning electronic and optical properties in lightweight carbon-based materials.

A rod with rounded ends is a noteworthy morphology, naturally encountered from large-scale roots to cells, and synthetically conceived down to nanomaterials. Rod-shaped anisotropic nanocrystals—especially those grown on pre-synthesized spherical seeds—play a major role in areas as different as photonics, cancer therapy, and photocatalysis. Nonetheless, despite decades of intense research, the anisotropic growth laws of nanorods (NRs) remain elusive. Here, we propose a general two-surface tension thermodynamic model that allows determining these axial and radial NR growth rates by reaction and diffusion. Depending on the initial seed size, three growth modes are predicted: either 3d, where both length and diameter grow simultaneously, 1d, where NRs just grow in one direction, and 1d-3d, showing the two growth modes sequentially. Modeling also shows that NRs lengthening and widening are driven by the surface tension ratio between the cylindrical core and the hemispherical tips. The confrontation of this model with kinetics data published on both high-symmetry face-centered-cubic (FCC) and lower-symmetry hexagonal close-packed (HCP) Wurtzite nanocrystals, as well as new experiments on Wurtzite CdSe-CdS NRs, confirms the existence of these three growth modes under reaction-limited conditions. From a practical point of view, they enable the determination of the axial/radial kinetic reaction rates along with surface tensions, and experimentally predict the seed-dependent growth and morphology of the NRs beyond the already well-established synthetic strategies for targeted applications. Finally, the few data published on the growth of Smectic A ligaments in the isotropic phase after a quench in temperature show a qualitative agreement with behaviors expected from a two-surface tension diffusion-limited mechanism.

${\mathrm{Th}}_2{\mathrm{Zn}}_{17}\text{−}\mathrm{type}$ structure-based permanent magnets, such as ${\mathrm{Sm}}_2{\mathrm{Fe}}_{17}{\mathrm{N}}_3$, offer strong potential as alternatives to neodymium magnets (NdFeB), but their practical use is limited by phase stability and the scarcity of Sm. Ce-based counterparts, particularly ${\mathrm{Ce}}_2{\mathrm{Fe}}_{17}{\mathrm{N}}_3$, are attractive low-cost candidates, yet their intrinsic planar magnetic anisotropy restricts permanent-magnet performance. Here, we induce uniaxial magnetic anisotropy in ${\mathrm{Ce}}_2{\mathrm{Fe}}_{17}{\mathrm{N}}_3$ through two approaches: (i) Co substitution on the Fe sublattice and (ii) partial substitution of Ce with Sm. Combined density functional theory and experimental results show that both strategies modify the $3d\text{–}4f$ interactions and band filling, yielding magnetization values up to $\sim 1.2\mathrm{T}$ and magnetocrystalline anisotropy energies exceeding $1\mathrm{MJ}/{\mathrm{m}}^3$ for Co-alloyed compositions, with significantly larger anisotropy achieved upon Sm substitution. In addition, the Sm-substituted ${\mathrm{Ce}}_2{\mathrm{Fe}}_{17}{\mathrm{N}}_3$ samples exhibit enhanced high-temperature stability compared to ${\mathrm{Sm}}_2{\mathrm{Fe}}_{17}{\mathrm{N}}_3$. These findings demonstrate that ${\mathrm{Ce}}_2{\mathrm{Fe}}_{17}{\mathrm{N}}_3$-based alloys can deliver magnetic performance suitable for permanent-magnet applications while reducing cost and reliance on critical rare-earth elements, and they provide practical design guidelines for rare-earth-lean magnets for energy and industrial applications.

We explore the intriguing topological itinerant magnet ${\mathrm{MgMn}}_6{\mathrm{Sn}}_6$, characterized by bilayer kagome Mn layers encasing a hexagonal Sn layer. Using ab initio density functional theory and dynamical mean-field theory calculations, we uncover the complex electronic properties and many-body configuration of its magnetic ground state. This frustrated many-body state stabilizes the ferromagnetic ground-state sector, providing the time-reversal–symmetry-broken background required for the nontrivial electronic structure. Consequently, the exchange-split topological bands and associated Berry-curvature response are intrinsically linked to the magnetic ground state. Our band dispersion calculations reveal a mirror symmetry-protected nodal line in the $k_z$ = 0 plane. When spin-orbit coupling is introduced, a gap is formed along the nodal line due to broken time-reversal symmetry with magnetic ordering, leading to substantial intrinsic Berry curvature. We identify Dirac fermions, van Hove singularities, and a flat band near the Fermi energy $\left(E_F\right)$, with spin-orbit coupling introducing a finite gap at key points. The unique proximity of the flat band to $E_F$ suggests potential instabilities. Spin-orbit coupling opens a 10 meV gap at the point of contact between the quadratic and flat bands, bestowing a nonzero ${\mathbb{Z}}_2$ invariant. This leads to a significant spin Hall conductivity. Despite the presence of large incoherent scattering due to electronic interactions, band crossings and flat band features persist at finite temperatures since the scattering does not impact these features near $E_F$. ${\mathrm{MgMn}}_6{\mathrm{Sn}}_6$ exhibits intriguing topological and magnetic properties, with promising applications in spintronics.

We report investigations into a new kind of multiferroic heterostructure consisting of a two-dimensional ferromagnetic 1T-phase ${\mathrm{FeCl}}_2$ monolayer and a sliding-ferroelectric bilayer-GaSe using first principles calculations. In this study, we determine the structural and electronic properties, energy band alignments, magnetic anisotropy, binding energies, interfacial charge transfer, and electric dipole moments of different stackings of $1\mathrm{T}\text{−}{\mathrm{FeCl}}_2/\mathrm{bilayer}\text{−}\mathrm{GaSe}$. The generalized gradient approximation of the Perdew–Burke–Ernzerhof (GGA-PBE) and Heyd-Scuseria-Ernzerhof (HSE) functionals predict half-metallicity, while the regularized-restored strongly constrained and appropriately normed (${\mathrm{r}}^2\mathrm{SCAN}$) functional opens a band gap in the spin-down Fe $3d$ states upon releasing symmetry constraints. The total magnetic moment of the ${\mathrm{Fe}}^{2+}$ ion (4.00 ${\mu }_B$) remains unchanged in the heterostructures for both polarization directions. The magnetic anisotropy energy of all stacking configurations considered indicates an in-plane easy magnetization axis, arising from the Fe-$d_{xz}$ orbitals under both polarization directions. All stackings exhibit Ohmic-type electrical conductivity, indicating charge transfer across the interfaces. Hence, this study presents a theoretical framework for designing artificial multiferroics that simultaneously maintain both ferromagnetic and ferroelectric properties, enabling future technological developments.

We report the epitaxial stabilization of GdAuSb films and GdAuSb/LaAuSb superlattices via molecular beam epitaxy on (0001)-oriented ${\mathrm{Al}}_2{\mathrm{O}}_3$ substrates. GdAuSb crystallizes in the Au-Au dimerized YPtAs structure type (space group $P{6}_3/mmc$), the same structure as the Dirac semimetal LaAuSb. Angle-resolved photoemission spectroscopy (ARPES) measurements show similar near $E_F$ bandstructures for GdAuSb and LaAuSb, plus a rigid band shift for GdAuSb toward more holelike behavior and corelike Gd $4f$ states $\sim 9\mathrm{eV}$ below the Fermi energy. LaAuSb/GdAuSb superlattices exhibit sharp superlattice fringes by x-ray diffraction and atomically precise interfaces by scanning transmission electron microscopy. Superlattices display two transitions in temperature-dependent resistvity, compared to a single Néel temperature for thick GdAuSb films. Superlattices of $Ln\mathrm{AuSb}$ materials ($Ln=$ rare earth) with atomically abrupt interfaces offer an epitaxial platform for control of magnetic and topological order via tunable intralayer exchange and reduced dimensionality.

Single crystals of the ternary transition metal silicide ${\mathrm{Zr}}_2{\mathrm{Ru}}_3{\mathrm{Si}}_4$ were successfully grown using flux method, and their superconducting properties were systematically investigated. ${\mathrm{Zr}}_2{\mathrm{Ru}}_3{\mathrm{Si}}_4$ crystallizes in a monoclinic structure featuring a quasi-one-dimensional structural framework. Electrical resistivity, magnetic susceptibility, and specific-heat measurements reveal bulk superconductivity with a transition temperature $T_c$ of 5.0 K. The temperature dependence of the upper critical field exhibits nearly isotropic behavior for different field orientations, indicating weak anisotropy in the superconducting state. Analysis of specific-heat data suggests a fully gapped $s$-wave superconducting order parameter. The electron-phonon coupling constant estimated from the McMillan equation indicates moderately strong coupling. Additional superconducting parameters, including the coherence length, penetration depth, and Ginzburg-Landau parameter, confirm that ${\mathrm{Zr}}_2{\mathrm{Ru}}_3{\mathrm{Si}}_4$ is a type-II superconductor in the dirty limit. These results provide detailed experimental insight into the superconducting behavior of single-crystalline ${\mathrm{Zr}}_2{\mathrm{Ru}}_3{\mathrm{Si}}_4$ and offer a valuable experimental basis for future studies of its electronic band structure and the potential interplay between superconductivity and the predicted nontrivial topological electronic states.

Oxygen vacancies are critical for determining the electrochemical performance of fast oxygen ion conductors. The perovskite ${\mathrm{La}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{CoO}}_3$, known for its excellent mixed ionic-electronic conduction, has attracted significant attention due to its favorable vacancy characteristics. In this study, we employ first-principles calculations to systematically investigate the impact of $3d$ transition-metal doping on the oxygen vacancy formation energies in the perovskite. Two magnetic states, namely the ferromagnetic and paramagnetic states, are considered in our models to capture the influence of magnetic effects on oxygen vacancy energetics. Our results reveal that the oxygen vacancy formation energies are strongly dependent on both the dopant species and the magnetic state. Notably, the magnetic states alter the vacancy formation energy in a dopant-specific manner due to double exchange interactions, indicating that relying solely on the ferromagnetic ground state may result in misleading trends in doping behavior. These findings emphasize the importance of accounting for magnetic effects when investigating oxygen vacancy properties in perovskite oxides.

${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ (Sr214) and related iridates have emerged as key platforms for fundamental correlated-electron physics and for potential applications such as magnonics. Here, we report the epitaxial growth of high-quality Sr214 thin films using reactive off-axis sputtering. Conventional pulsed-laser deposition of Sr214 suffers from limitations arising from the volatility and decomposition of iridates, which often result in parasitic Ruddlesden–Popper phases and iridium vacancies. By employing sputtering, we mitigate these issues and achieve stable growth conditions that allow precise mapping of the phase diagram. Systematic variation of the growth temperature reveals that Sr214 stabilizes within a window between $825{}^{\circ }\mathrm{C}$ and $1050{}^{\circ }\mathrm{C}$, with optimal crystallinity and thickness obtained at $840{}^{\circ }\mathrm{C}$. Raman spectroscopy provides sensitive diagnostics of iridium vacancies, with defect-induced phonon modes and peak intensity ratios correlating strongly with the $c$-axis lattice parameter. Our results establish reactive sputtering as a robust route for integrating Sr214 into oxide electronic and magnonic device architectures.

The magnetic material ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$ (MBT) has garnered significant attention due to its unique combination of long-range antiferromagnetism and nontrivial topological electronic properties. However, experimental measurements report inconsistent magnetizations, which could be attributed to a variety of intrinsic defects. To date, a comprehensive investigation of defect-engineered MBT systems has not yet been established. Employing state-of-the-art $abinitio$ techniques, this work systematically investigates the influence of various experimentally reported defects on the magnetic properties of bulk and monolayer MBT at different concentrations. Mn-vacancy and Mn-rich defects are found to enhance the ferromagnetism of bulk MBT. The investigation of Mn-rich and intermixing defects in the monolayer reveals that subtle structural and electronic modifications can alter the magnetic coupling. Projection onto a Heisenberg Hamiltonian demonstrates that defects modify exchange interactions, thereby giving rise to distinct magnetic ground states. This work sheds light on magnetic coupling mechanisms and provides guidelines for the experimental control of magnetism in ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$.

The magnetic damping of spin-pumping heterostructures consisting of Pt and ${\mathrm{Ni}}_{80}{\mathrm{Fe}}_{20}$ (Permalloy, Py) thin films is studied via temperature- and frequency-dependent ferromagnetic resonance (FMR). Additional magnetic and structural characterization is done by transmission electron microscopy (TEM), x-ray absorption spectroscopy, and x-ray magnetic circular dichroism (XMCD). The frequency-dependence of the FMR linewidth allows to extract the Gilbert damping parameter $\alpha$ as a function of temperature. Py in direct contact with Pt exhibits a strong enhancement of $\alpha \left(T\right)$, and the dependence on the thickness of the Py layer suggests this to be an interfacial effect. The enhanced $\alpha \left(T\right)$ is accompanied by an induced magnetic polarization of the Pt as evidenced by XMCD, while the other magnetic properties of Py as measured with FMR and static magnetometry remain virtually unchanged. The increase of $\alpha \left(T\right)$ can be efficiently suppressed by the insertion of an Al-spacer layer between Pt and Py as thin as 1 nm, which coincides with the loss of the magnetic polarization of Pt.

${\mathrm{U}}_3{\mathrm{Si}}_2$ is a promising accident-tolerant nuclear fuel, yet its elastic properties remain poorly understood because of significant discrepancies between experimental measurements, including bulk moduli ranging from $\sim 68\mathrm{GPa}$ (RUS) to $\sim 107\mathrm{GPa}$ (XRD), the origin of which has remained unresolved. In this work, we investigate the structural, thermodynamic, and elastic properties of ${\mathrm{U}}_3{\mathrm{Si}}_2$ from 0 to 1500 K using density functional theory in the $\mathrm{DFT}+U$ approach combined with machine-learning-assisted canonical sampling and interatomic potentials. The use of the PBEsol functional and a $U$ value of 2.0 eV enables us to simultaneously suppress the spurious structural distortion of previous calculations and reproduce the experimental equilibrium volume, which is a prerequisite for a reliable determination of the full tetragonal elastic tensor. We further demonstrate that explicit finite-temperature sampling is essential to capture the full thermal softening of the elastic constants, as static calculations at thermally expanded volumes underestimate this effect by up to 30% for certain elastic constants. Finally, we demonstrate that the apparent conflict between high pressure XRD and RUS bulk moduli arises from the pronounced elastic anisotropy of the tetragonal lattice combined with the isotropic approximations used in RUS data analysis and the effects of sample porosity. These findings provide a consistent set of temperature-dependent elastic properties for ${\mathrm{U}}_3{\mathrm{Si}}_2$ and resolve long-standing discrepancies between experimental measurements.

Antiperovskites share the same structure as perovskites, but allow completely different chemistries and nominal charge states of anions to be stabilized. This gives rise to many interesting phenomena, including septet superconductivity and topological crystalline insulating phases in these systems. Despite this, the work on the crystal structural trends in these compounds is more limited compared to perovskites. In this study, we consider the family of antiperovskite oxides with tetrel elements (Si, Ge, Sn, Pb) and alkaline earth metals (Ca, Sr, Ba), and perform a detailed study of their crystal structures using first-principles density functional theory. We show how tolerance factor arguments can be constructed to predict their structure in a way parallel to the perovskites, and furthermore, how heterostructuring (or cation-order) can be used to induce ferroelectricity in these systems which may provide an experimental knob to modify electronic structure. We conclude with a discussion of the electronic structure of antiperovskites, and show that they display interesting trends not observed in regular perovskites, including significant antibonding interactions between face-center ions, which might need to be taken into account when building effective electronic models of these compounds.

We report the evolution of the antiferromagnetic domain structure of epitaxial ${\mathrm{La}}_{0.45}{\mathrm{Sr}}_{0.55}{\mathrm{MnO}}_3$ (LSMO) ultrathin films with thickness in the range from 5–50 unit cells (uc), using x-ray photoemission electron microscopy (XPEEM). While the 5 uc thick LSMO shows no magnetic contrast down to $\sim 80\mathrm{K}$, thicker films display a multidomain antiferromagnetic configuration with a nonmonotonic variation in the characteristic domain size from 0.3 $\mu \mathrm{m}$ at 10 uc, to 3–5 $\mu \mathrm{m}$ at 15–16 uc and 1 $\mu \mathrm{m}$ for 50 uc. Post-growth annealing is found not to impact strongly the magnetic domain state. In contrast, for a 15 uc film grown on a substrate characterized by large atomic steps $(\sim 1\mu \mathrm{m})$, we observe much larger antiferromagnetic domains and the presence of net magnetic moment in the form of stripes with alternating contrast, assigned to the signal from the top uncompensated spins of the A-type antiferromagnetic state of LSMO. From the combined antiferromagnetic domain structure and the net magnetic moment contrast, we determine the exact orientation of the Néel vector, including at domain walls. We describe the antiferromagnetic domain size distribution in terms of interface and bulk contributions to the density of defects that pin the antiferromagnetic domain walls and which determine the equilibrium domain configuration. Our results demonstrate the impact of thickness and defects on the antiferromagnetic domain size and constitute a stepping stone in controlling the antiferromagnetic domain state required for oxide antiferromagnetic device applications.

Photoelectron excitations in oxide heterostructures routinely elicit both surface photovoltage and open-circuit voltage. Surface photovoltage measurements are hence often used as a proxy to gauge open-circuit voltage response. Here, we present a method for studying photovoltaic effects in oxide heterostructures by concurrently measuring, with an atomic force microscope, surface photovoltage $\left(\mathrm{\Delta }{V}_{\mathrm{SPV}}\right)$ and open-circuit voltage $\left(V_{\mathrm{OC}}\right)$ while varying illumination wavelength and intensity. This combined method is applied at super- and subband-gap illumination wavelengths on ${\mathrm{Bi}}_2{\mathrm{FeCrO}}_6/\mathrm{Nb}\text{−}{\mathrm{SrTiO}}_3$ heterostructures annealed under various oxidative and reductive conditions. The results show that $\mathrm{\Delta }{V}_{\mathrm{SPV}}$ consistently reflects interfacial photocarrier generation, whereas $V_{\mathrm{OC}}$ is more governed by photocarrier transport, sensitive to recombination. It is also shown that deep oxygen-vacancy levels act as recombination centers, whereas shallow cation-vacancy levels impact depletion region width. Experimental observations are consistent with DFT density of states of crystals containing isolated and coupled vacancies. Together, $\mathrm{\Delta }{V}_{\mathrm{SPV}}$ and $V_{\mathrm{OC}}$ spectroscopies—applied across multiple excitation energies and intensities—offer valuable insights into mechanisms governing photon-induced electrical power generation in photovoltaic oxide heterostructures.

Using first-principles calculations and ab initio molecular dynamics, we investigate the formation of atomic vacancies in the monolayer ${\mathrm{AsBiSe}}_3$ and its consecutive effect on electronic and mechanical properties. The calculated formation energies reveal that Se vacancies constitute the most stable defect. The energy barrier for the migration of these vacancies between neighboring atomic sites is 1.50 eV, surpassing the barrier energies for the migration of As (1.19 eV) and Bi (0.76 eV) vacancies, confirming their stability. Regarding mechanical properties, we have systematically investigated the mechanical response of all defect configurations considered in the ${\mathrm{AsBiSe}}_3$ monolayer. The presence of most-stable Se atomic vacancies does not destroy the semiconducting character of ${\mathrm{AsBiSe}}_3$ but it gives rise to midgap states that could impact the optical and transport characteristics of ${\mathrm{AsBiSe}}_3$, suggesting avenues for additional research.

Understanding gas adsorption on defect-engineered two-dimensional (2D) materials is essential for advancing applications in energy storage, catalysis, and sensing. In this work, first-principles calculations are employed to systematically investigate the adsorption behaviors of ${\mathrm{H}}_2,{\mathrm{O}}_2,{\mathrm{H}}_2\mathrm{O},\mathrm{CO}$, and ${\mathrm{CO}}_2$ at sulfur vacancy $V_{\text{S}}$ sites in both single-component transition metal dichalcogenides ${M\mathrm{S}}_2$ (M = W, Mo, Ta, Nb, and V) and high-entropy ${\left(\mathrm{WMoTaNbV}\right)}_{\mathrm{S}2}$ monolayers. In ${M\mathrm{S}}_2$ systems, $V_{\text{S}}$ introduces localized defect states that enhance surface reactivity, leading to diverse adsorption modes including physisorption, chemisorption, and dissociative adsorption. Notably, ${\mathrm{H}}_2$ dissociation is kinetically favorable on $V_{\text{S}}/{\mathrm{TaS}}_2$ and $V_{\text{S}}/{\mathrm{NbS}}_2$, while ${\mathrm{CO}}_2$ remains weakly physiosorbed across all single-metal systems. In contrast, high-entropy ${\left(\mathrm{WMoTaNbV}\right)}_{\mathrm{S}2}$ exhibits a continuous distribution of adsorption energies due to its diverse local coordination environments and synergistic multimetal interactions. This results in significantly reduced activation barriers for ${\mathrm{H}}_2$ dissociation, enhanced adsorption strength for ${\mathrm{O}}_2,{\mathrm{H}}_2\mathrm{O}$, and CO, and a transition of ${\mathrm{CO}}_2$ adsorption from physisorption to chemisorption. Electronic structure analyses reveal that these improvements originate from multicenter $d\text{−}p$ orbital hybridization and enhanced charge transfer at vacancy sites. Overall, the high-entropy design effectively tailors the adsorption landscape of 2D transition metal dichalcogenides, offering a promising strategy for developing advanced materials for hydrogen storage, ${\mathrm{CO}}_2$ activation, and gas-sensing applications.