arXiv subjects

Shahar Zuri

Publications and source records attributed to Shahar Zuri.

6 recordsLinked to original sources

arXiv2026

Localized Exciton Emission with Spontaneous Circular Polarization in NiPS3/WSe2 Heterostructures

Two-dimensional (2D) van der Waals (vdW) heterostructures (HSs) provide a versatile platform for tailoring electronic, optical, and magnetic properties via proximity effects at their interfaces. In this work, we explore the optical response of few-layer NiPS3/WSe2 HSs using low-temperature micro-photoluminescence ({\mu}-PL) and magneto-PL spectroscopy. The HSs exhibit multiple sharp excitonic peaks that do not appear in the individual constituent materials, indicating the emergence of localized intralayer WSe2 excitons confined by interface-induced potentials. Notably, these excitons exhibit spontaneous circular polarization even in the absence of an external magnetic field, suggesting a magnetic proximity effect induced by uncompensated spins at the NiPS3 interface. Magneto-PL measurements further reveal nonlinear Zeeman splitting, consistent with the presence of an interfacial exchange field that alters the valley exciton dynamics. Density functional theory (DFT) calculations confirm the intralayer origin of the PL and reveal interfacial hybridization and spin texture modifications, supporting the experimental findings. These results highlight how combining a 2D semiconductor with a layered antiferromagnet enables control over valley polarization and spin degrees of freedom, offering new opportunities for chiral light sources and magnetically tunable optoelectronic devices.

cond-mat.mtrl-sci↗

arXiv2026

Crystal Anisotropy Implications on the Magneto-Optical Properties of van der Waals FePS3

Antiferromagnetic FePS3 has recently gained significant interest in its potential applications in spin-related devices. Here, we show that in-plane structural anisotropy has a major impact in shaping the optical responses of FePS3 single-crystals from the bulk form down to the monolayer limit. X-ray diffraction on a bulk FePS3 crystal confirms a distorted FeS6 octahedron causing inequivalent Fe-Fe distances and consequently resulting in a higher a/b lattice parameter ratio. Micro-photoluminescence observations on bulk and monolayer FePS3 reveal four emissions: one intra-atomic d-d transition (band A, centered at ~1.24 eV) and three p-d charge transfer transitions (bands B, C, and D, centered around ~1.79 eV, ~2.3 eV, and ~2.56 eV, respectively). These bands exhibit different polarization behaviors, which persist down to the monolayer limit. Density functional theory calculations from bulk to monolayer FePS3 reveal the underlying electronic structure, assign the observed emissions, and indicate why these peaks have contrasting linear and circular polarization responses. These results establish a direct structure-optics relation in FePS3, highlighting the strong coupling between lattice anisotropy, electronic transitions, and symmetry-selective optical selection rules.

cond-mat.mtrl-sci↗

arXiv2024

Tuning Magnetic and Optical Properties in MnxZn1-xPS3 Single Crystals by the Alloying Composition

The exploration of two-dimensional (2D) antiferromagnetic (AFM) materials has shown great promise and interest in tuning the magnetic and electronic properties as well as studying magneto-optical effects. The current work investigates the control of magneto-optical interactions in alloyed MnxZn1-xPS3 lamellar semiconductor single crystals, with the Mn/Zn ratio regulating the coupling strength. Magnetic susceptibility results show a retention of AFM order followed by a decrease in N\'eel temperatures down to ~ 40% Mn concentration, below which a paramagnetic behavior is observed. Absorption measurements reveal an increase in bandgap energy with higher Zn(II) concentration, and the presence of Mn(II) d-d transition below the absorption edge. DFT+U approach qualitatively explained the origin and the position of the experimentally observed mid band-gap states in pure MnPS3, and corresponding peaks visible in the alloyed systems MnxZn1-xPS3. Accordingly, emission at 1.3 eV in all alloyed compounds results from recombination from a 4T1g Mn(II) excited state to a hybrid p-d state at the valence band. Most significant, temperature-dependent photoluminescence (PL) intensity trends demonstrate strong magneto-optical coupling in compositions with x > 0.65. This study underscores the potential of tailored alloy compositions as a means to control magnetic and optical properties in 2D materials, paving the way for advances in spin-based technologies.

cond-mat.mtrl-sci↗

arXiv2022

Uncovering Multiple Intrinsic Chiral Phases in (PEA)2PbI4 halide Perovskites

Two-dimensional (2D) halide perovskites offer a unique platform to investigate the ground-state of materials possessing significant anharmonicity. In contrast to three-dimensional perovskites, their 2D counterparts offer substantially fewer degrees of freedom, resulting in multiple well-defined crystal structures. In this work, we thoroughly investigate the anharmonic ground-state of the benchmark (PEA)2PbI4 compound, using complementary information from low-temperature x-ray diffraction (XRD) and photoluminescence spectroscopy, supported by density functional theory (DFT) calculations. We extrapolate four crystallographic configurations from the low-temperature XRD. These configurations imply that the ground-state has an intrinsic disorder stemming from two coexisting chiral sub-lattices, each with a bi-oriented organic spacer molecule. We further show evidence that these chiral structures form unevenly populated ground-states, portraying uneven anharmonicity, where the state population may be tuned by surface effects. Our results uncover a disordered ground-state that may induce intrinsic grain boundaries, which cannot be ignored in practical applications.

cond-mat.mtrl-sci↗

arXiv2022

Crystal anisotropy implications on the intrinsic magnetic and optical properties in van der Waals FePS3

Antiferromagnetic (AFM) FePS3 has gained significant interest recently for its potential applications in spin-related devices. A single layer is comprised of a honeycomb network, stabilized by long-range spin-exchange interactions, with a zigzag or Neel arrangement of the Fe-atoms. This study exposed, for the first time, a strong impact of lateral crystal distortion on the magnetic arrangement and optical properties of FePS3. This impact was deciphered by correlating photoluminescence (PL) observations with single-crystal XRD which uncovered anisotropy in the a/b crystallographic plane. Thus, induceing a breakage in the inversion symmetry in FePS3 causing changes in it's electronic and optical transitions. The MPL observations exhibited an unexpected band-edge circularly polarized recombination emission, while off-band-edge transitions were linearly polarized. Also, temperature-dependent MPL measurements reflected zigzag-AFM at low temperatures and the coexistence of zigzag or Neel at mid temperatures. Theoretical calculation implementing anisotropy in spin-exchange interactions among Fe atom's nearest neighbors revealed stabilized zigzag arrangement tilted away from the a-axis. Furthermore, DFT calculations of the electronic band-edge predicted split states in degenerate symmetric points (K+/K-) for zigzag structure and non-degenerate for the Neel arrangement. Highlighting the importance of the inclusion of a crystallographic anisotropy parameter for the simulation of the experimental observations.

cond-mat.mtrl-sci↗

arXiv2020

Lubricated gravity currents of power-law fluids

The motion of glaciers over their bedrock or drops of fluid along a solid surface can vary dramatically when these substrates are lubricated. We investigate the coupled flow of a gravity current (GC) of strain-rate softening fluid that is lubricated by a denser, lower-viscosity Newtonian fluid. We present a set of experiments in which such GCs are discharged axisymmetrically and at constant flux over a flat surface. Using imaging techniques we follow the front evolution of each fluid and their thickness field. We find that the two fronts of our lubricated GCs evolve faster than non-lubricated GCs, though with similar time exponents. In addition, the thickness of the non-Newtonian fluid is nearly uniform while that of the lubricating fluid is nonmonotonic with localised spikes. Nevertheless, lubricated GCs remain axisymmetric as long as the flux of the lubricating fluid is sufficiently smaller than the non-Newtonian fluid flux.

physics.flu-dyn↗