The creation and exploration of new materials under extreme pressure-temperature conditions has become increasingly reliant on laser-heated diamond anvil cell (LHDAC) techniques, which provide direct access to previously unexplored regions of multinary phase diagrams. Whereas numerous high-pressure phases have been identified in situ, systematic recovery and post-synthesis physical property characterization of these materials remain significant challenges. In this work, we present the development of an integrated LHDAC synthesis and demonstrate a practical LHDAC-based synthesis workflow that enables stabilization and recovery of metastable intermetallic phases for subsequent structural and transport studies. Using this approach, we successfully achieved LHDAC synthesis of high-pressure MnSb2 and YbZn2 phases under moderate pressures. Synchrotron X-ray diffraction and spatial mapping confirm dominant formation of the targeted phases, whereas laboratory-based refinement quantifies phase fractions despite intrinsic microstrain and minor secondary phases. High-pressure transport measurements on recovered samples reveal tunable by pressure electronic instabilities in both systems. In MnSb2, pressure suppresses two high-temperature magnetic ordering anomalies, observed in transport, by 5 GPa and for higher pressures induces a new low-temperature feature that increases with further pressure increase. In hexagonal high-pressure YbZn2, an electronic reconstruction emerges at 11 GPa, characterized by semiconducting-like behavior from 30 K to 300 K and a broad low-temperature coherence crossover near 30 K. Our results establish LHDAC synthesis not only as a structural discovery tool, but also as an experimental platform for investigating correlated quantum states stabilized far from equilibrium thermodynamic conditions.

Ultrafast spectroscopy under simultaneous high pressure and magnetic field provides a versatile approach for investigating pressure-driven electronic instabilities and correlated phases, and for probing potential bulk superconducting behavior under extreme conditions. However, such an experimental platform has yet to be implemented, standing as a roadblock to a fuller understanding of nonequilibrium superconductivity and vortex-controlled quasi-particle (QP) dynamics. Here, we bridge this capability gap by developing high pressure (up to 40 GPa), high magnetic field (up to 7 T), cryogenic (down to 5 K) femtosecond spectroscopy, and using it to probe magneto-pressure evolution of quasiparticle dynamics in the trilayer nickelate Pr_4Ni_3O_10. We observe pronounced critical slowing down of QP relaxation at the charge-density-wave transition, which collapses under applied pressure. At higher pressures, the relaxation instead lengthens at low temperature, consistent with incipient superconducting correlations. However, the negligibel magnetic-field-dependence up to 7 T and absence of vortex-induced pre-bottleneck dynamics–robust signatures observed in our controlled bulk superconducting samples–indicates that any superconducting state under the present pressure conditions is likely non-bulk, filamentary, or strongly inhomogeneous. The magneto-pressure ultrafast capability opens a new avenue for resolving outstanding questions surrounding pressure-induced superconductivity and intertwined orders in correlated quantum materials.

La2Ni7 is an itinerant magnetic system with a small ordered moment of similar to 0.1 & micro;B/Ni and a series of antiferromagnetic (AFM) transitions at T1 = 61.0 K, T2 = 56.5 K, and T3 = 42.2 K. M(H), and rho(H) isotherms as well as constant field M(T) and rho(T) measurements on single-crystalline samples manifest a complex, anisotropic H-T phase diagram with multiple phase lines. Here we present the growth and characterization of single crystals of the La2(CuxNi1-x)7 series for 0 x 0.181. We measured powder x-ray diffraction and composition, as well as anisotropic temperature-and field-dependent resistivity, temperature-and field-dependent magnetization, and temperature-dependent heat capacity on these single crystals. Using the measured data we infer a transition temperature-composition (T-x) phase diagram for this system to study the evolution of the AFM ordering upon Cu substitution. For 0 x 0.097, the system remains magnetically ordered at base temperature with x 0.012, showing signs of multiple AFM ordering temperatures. For the higher substitution levels 0.125 x 0.181, there are no signatures of magnetic ordering, but anomalous features in resistance and heat capacity data are observed which are consistent with the Kondo effect in this system. The intermediate x = 0.105 sample lies between the magnetic ordered and the Kondo regime and is in the vicinity of the AFM quantum critical point (QCP). Thus, La2(CuxNi1-x)7 is an example of a small moment system that can be tuned through a QCP. Given these data combined with the fact that the La2Ni7 structure has kagomelike, Ni sublattices running perpendicular to the crystallographic c axis, and a predicted 3d-electron flat band that contributes to the density of states near the Fermi energy, La2(CuxNi1-x)7 becomes a promising system to host and study exotic physics.

Scanning Tunneling Microscopy is a cornerstone technique for visualizing the electronic density of states with atomic resolution (typically below 0.1 nm). While the field of view of most STM setups extends up to a few microns, obtaining atomic resolution over these large areas is often impractical and excessively time-consuming. This is due to the need to acquire maps with a point number reaching 10^7 or more with a full current or conductance vs voltage curve at each point. The standard procedure is to make large scale maps and then select small regions to zoom-in for high-resolution atomic scale analysis. However, this approach fails to address a question which is often critical: Does a specific atomic-scale modulation of the electronic density of states persist over much larger, mesoscopic length scales? Here we present a new method: Replica STM (R-STM), that overcomes this limitation, allowing the study of atomic-scale phenomena up to micron length scales. We obtained new large-area STM tunneling conductance maps in UTe_2 and FeSe, spanning areas over 200 nm in size. In these large scale maps we discovered periodic signals with wavelengths significantly exceeding interatomic distances. We show that these large-wavelength periodic signals are replicas of the underlying atomic-scale density of states modulations. R-STM leverages these replica signals to efficiently track atomic-scale features over large areas. We discuss the influence of phase slips, disorder and defects in the replicas. Our results suggest that atomic scale modulations of the superconducting density of states could persist over large length scales in FeSe. R-STM provides a new capability for STM to compare atomic scale with micrometer scale phenomena. The proof of principle of R-STM can be extended to any other scanning probe microscopy experiment where a periodic signal is traced as a function of position.

SrNi_2P_2 represents a unique case of a collapsed structural phase (one-third collapsed, where one out of every three P-P pairs forms a bond) in the A(TM)_2X_2 family of compounds (A = alkali metal, alkaline-earth metal, or rare earth; TM = transition metal; X = pnictogen). Furthermore, Co doping studies aimed at understanding the interrelationship between this unusual bonding motif and the resulting physical properties produced a magnetically rich phase diagram, specifically on the Co-rich side of the phase diagram. However, important questions remained regarding the detailed nature of the magnetic ground states. To address these issues, we performed single-crystal neutron diffraction measurements on Sr(Ni_1-xCo_x)_2P_2 with compositions x = 0.88, 0.94, and 0.97. For x = 0.88 and 0.94, the measurements reveal incommensurate helical magnetic order with a doping-dependent propagation vector (0,0,τ), similar to that observed in Sr(Ni_1-xCo_x)_2As_2. In contrast, the x = 0.97 composition shows clear signatures of a ferromagnetically ordered ground state, resolving the earlier ambiguity regarding the nature of the low-temperature phase. Furthermore, our results highlight the subtle balance between these competing ground states, whose evolution does not appear to be fully captured by the conventional frameworks of either itinerant or local-moment Heisenberg models typically applied to related 122 systems.

Marcasite-type compounds have been proposed as promising hosts of exotic magnetic quantum states, yet experimental realizations in stoichiometric, disorder-free systems remain limited. Here, we report the high-pressure stabilization and magnetic characterization of MnSb_2, a marcasite-type compound that is thermodynamically metastable under ambient pressure. Single crystals were synthesized using a cubic multi-anvil press, and powder and single-crystal X-ray diffraction confirm the orthorhombic Pnnm structure. These crystals are stable at ambient pressure for a long time up to between 450-500 K. Heat-capacity measurements reveal phase transitions at approximately 220 K and 118 K. Neutron diffraction uncovers an unconventional magnetic ground state below 220 K. Magnetic powder neutron diffraction refinements reveal possible multiple magnetic configurations that provide comparably acceptable fits to the experimental data. While most solutions are consistent with a spin-density-wave (SDW) description, helical models systematically yield inferior agreement factors. Across a broad range of models, the Mn ordered moment reaches a maximum value of approximately 2 μ_B and remains predominantly collinear, with minimal canting along the c-axis. At 200 K, the magnetic propagation vector is q = (0, 0.3975, 0.3783); upon cooling, the b component increases toward 0.5, reflecting a temperature-dependent evolution of the modulation. The need for modification of the magnetic model between high and low temperatures further highlights the complex and strongly temperature-dependent nature of the magnetic order in this system. These results establish MnSb_2 as a pressure-stabilized marcasite magnet with a highly tunable, complex magnetic ground state and a compelling stoichiometric platform for exploring unconventional magnetic behavior, including potential altermagnetism.

We report the dielectric and magnetic properties of epitaxial thin films of the high entropy oxide (HEO) perovskite Nd(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3, which orders magnetically below T mag approximate to 190 K. At T >> T mag, the dielectric response reveals a Debye-type frequency dependence with a zero-frequency dielectric constant of approximate to 230-250. The dc bias voltage loops of are reversible but exhibit three distinct peaks centred at zero and finite positive and negative voltage. We provide evidence that the zero-bias peak is governed by the oxygen sublattice while the finite bias peaks originate from cationic dipoles. The maximal response of the latter appears to be shifted to finite bias by a static uncompensated electric field due to a vertical gradient of the oxygen content. Below T mag, this anomalous dielectric response is strongly suppressed, presumably by magnetostriction that counteracts and freezes the ionic displacements. These findings indicate a unique correlation between configurational entropy, dielectric response, and magnetic properties. In combination with a large dielectric strength, it enables a non-hysteretic tuning of the dielectric response of magnetoelectronic devices with multiple parameters like temperature, electric, and magnetic field. This HEO is equally interesting for fundamental studies of competing electric and magnetic orders in strongly disordered materials.

The creation and exploration of new materials under extreme pressure-temperature conditions has become increasingly reliant on laser-heated diamond anvil cell (LHDAC) techniques, which provide direct access to previously unexplored regions of multinary phase diagrams. Whereas numerous high-pressure phases have been identified in situ, systematic recovery and post-synthesis physical property characterization of these materials remain significant challenges. In this work, we describe the setup and implementation of an LHDAC-based synthesis and recovery workflow and demonstrate its application to metastable MnSb2 and YbZn2 phases. Synchrotron x-ray diffraction and spatial mapping confirm dominant formation of the targeted phases, whereas laboratory-based refinement quantifies phase fractions despite intrinsic microstrain and minor secondary phases. High-pressure transport measurements on recovered samples reveal pressure-tunable electronic instabilities in both systems. In MnSb2, pressure suppresses two high-temperature magnetic ordering anomalies, observed in transport, by similar to 5 GPa and, for higher pressures, induces a new low-temperature feature that increases with further pressure increase. In hexagonal high-pressure YbZn2, an electronic reconstruction emerges at similar to 11 GPa, characterized by semiconducting-like behavior from similar to 30 to 300 K and a broad low-temperature coherence crossover near 30 K. Our results establish LHDAC synthesis not only as a structural discovery tool but also as an experimental platform for investigating correlated quantum states stabilized far from equilibrium thermodynamic conditions.

Two-dimensional van der Waals (vdW) magnets are attracting significant attention, both as platforms for studying fundamental magnetic interactions and for the exciting possibility of utilizing them as building blocks in devices and heterostructures, which may lead to new physical phenomena and functionalities. Here, we provide a detailed study of the crystal structure and physical properties of the recently discovered vdW ferromagnet FePd2Te2. We find this compound has a relatively wide width of formation, and grow single crystals with compositions FexPdyTe2 where x ranges from 0.9 to 1.1 and y from 1.8 to 2.5, respectively. Temperature-dependent X-ray diffraction and transport measurements reveal that a first-order structural transition occurs in the range of T = 360-420 K, where the critical temperature, modulation wave vector, and corresponding room-temperature crystal structures all depend on chemical composition. Above the transition, the compounds with Pd fraction y > 2 adopt a disordered derivative of the tetragonal FeTe structure, with the Fe layer showing mixed Fe/Pd occupancy and the extra Pd atoms partially occupying interstitial sites. Below 370 K, the structure is incommensurately modulated, likely associated with the complex ordering of Pd/Fe atoms in the metal layers or the interstitial Pd in the vdW gaps. For y < 2, the composition Fe1.1Pd1.8Te2 has monoclinic symmetry at room temperature that is consistent with the reported structure of FePd2Te2. This phase undergoes a structural transition at 420 K for which the high temperature structure is yet to be determined; however, based on the similarities with the y > 2 compounds, we speculate that its T > 420 K structure is also tetragonal. Importantly, the high temperature, symmetry-breaking structural transition observed here provides a likely explanation for the origin of the structural domains previously observed in FePd2Te2. All compounds investigated in the FexPdyTe2 series show metallic behavior, with magnetic characterization indicating that they are easy-plane, hard, ferromagnets with T-C spanning 98-180 K. Both the critical temperature for the structural transition and the Curie temperature are moderately suppressed with increasing Pd fraction y and corresponding decreasing Fe fraction x, indicating that synthetic control over x and y paves way for the further exploration of these compounds.

LaCrGe3 is a metallic, itinerant ferromagnet with T-C approximate to 86 K and an easy magnetic direction along its hexagonal c axis. Here we present studies of the H||c Hall effect in LaCrGe(3 )at ambient pressure and under pressures up to 24 kbar. At ambient pressure the anomalous Hall conductivity in the ferromagnetic state reaches a large value of similar to 520 Omega(-1 )cm(-1). The overall data are consistent with the behavior expected for a ferromagnet with magnetic field applied along its easy axis. Measurements under pressure yield an H = 0, P-T phase diagram consistent with earlier publications with T-C being suppressed with pressure and nonferromagnetic phases appearing for P> 15 kbar. The data suggest that the observed T-C suppression is due to the pressure-dependent exchange interactions rather than suppression of the size of the magnetic moment. Field-dependent Hall resistivity in the higher-pressure, nonferromagnetic state is consistent with the net moment being zero for H = 0. In a finite field there is a sharp anomaly comparable to the one associated with a spin-flip metamagnetic transition. The H-T phase diagrams corresponding to a pressure-induced magnetic phase are constructed for several pressures. The Hall data suggest the possibility of the pressure-induced nonferromagnetic phase being a combination of multiple small regions of antiferromagnetic phases with different wave vectors.

The combination of localized magnetic moments, their frustration and interaction with itinerant electrons is a key challenge of condensed matter physics. Frustrated magnetic interactions promote degenerate ground states with enhanced fluctuations, a topic that is predominantly studied in magnetic insulators. The coupling between itinerant and localized electrons in metals add complexity to the problem, and is presently formulated only for extreme cases in which the itinerant electrons mediate exchange between localized spins (RKKY interaction) or suppress the formation of magnetic moments (Kondo screening). Here, we report an in-depth experimental study of the distorted Kagome metal YbAgGe, unravelling the open questions of how frustration, localized magnetism and itinerant electrons are intertwined in frustrated Kondo metals. We find that coupled itinerant and localized electrons give rise to dynamic magnetic correlations below T* ≈ 20 K. At lower temperature, frustrated magnetic interactions establish anisotropic magnetic short-range correlations that culminate into antiferromagnetic long-range order below TN = 0.68 K with a significantly reduced modulated magnetic moment. We show that local moment Hamiltonians can yield limited understanding of the microscopic behaviour in frustrated metals, and prompt the extension of more sophisticated model Hamiltonians incorporating itinerant effects. The interplay of localized magnetic moments, frustration, and itinerant electrons in metals remains a complex challenge in condensed matter physics. Here, the authors investigate the distorted Kagome metal YbAgGe, revealing dynamic magnetic correlations and anisotropic short-range order, prompting advanced models to better understand frustrated Kondo metals.

The compound SrNi_2P_2 can exhibit multiple crystal structures with no P-P pairs bonded (uncollapsed tetragonal, or ucT, state), with one-third of the P-P pairs bonded (one-third collapsed orthorhombic, or tcO, state), or with all P-P pairs bonded (collapsed tetragonal, or cT, state) across the Sr layers. The system can be tuned into its different states by changing temperature, mechanical stress, or chemical composition. Changes in bonding may manifest in changes of macroscopic properties of the material, such as its shape, electrical conductivity, or magnetism. In this work, we show that SrNi_2P_2 can be tuned among the three states by changing Cu substitution and temperature. We present temperature-dependent resistance and single-crystal x-ray diffraction results in Sr(Ni_1-xCu_x)_2P_2 single-crystals that show that Cu substitution favors the P-P bonding, stabilizing the cT state at ambient pressure. We construct a T-x phase diagram that shows how all of these transition temperatures increase with increasing Cu fraction, x. The transition between the tcO state and the cT state exhibits a very large thermal hysteresis, which can be tuned to temperatures close to room temperature. In particular, the properties of Sr(Ni_0.963Cu_0.037)_2P_2 may make it suitable for applications as a shape memory material at room temperature.

Type-II superconductors under magnetic fields are in a quantum coherent non-dissipative state as long as vortices remain pinned. Dissipation appears when vortices depin, eventually driven by thermal fluctuations. This can be associated to a melting transition between a vortex solid and a vortex liquid. This transition is almost always observed very close to T$_c$ when probed by macroscopic experiments. However, it remains unclear how the vortex solid responds to thermal fluctuations at the scale of individual vortices far from the melting transition. Here we use scanning tunneling microscopy (STM) to visualize vortices in CaKAs$_4$Fe$_4$ (T$_c \approx$ 35 K). We find vortex liquid droplets-localized regions in space where vortices strongly fluctuate due to thermal exctiation-at temperatures as low as 0.5\,T$_c$. Our results show that the onset of dissipation at the local scale occurs at temperatures considerably below T$_c$ in type-II superconductors.

Mixed valency in intermetallics with lanthanide cations is well established as a pathway to unusual charge transport, complex magnetism, and superconductivity. In this work, we report a comprehensive study of the structural, magnetic, electronic, and thermal properties of the mixed valent compound CeFe2Ga8. Powder X-ray diffraction (PXRD) and X-ray photoelectron spectroscopy (XPS) characterize CeFe2Ga8 as a quasi-one-dimensional (Q1D) compound with mixed-valent Ce3+ and Ce4+ on a single crystallographic site. 57Fe M & ouml;ssbauer spectroscopy shows that the Fe sublattice is nonmagnetic, in direct contrast to recent reports on this compound. Low-temperature electrical resistivity and heat capacity measurements show no evidence of magnetic ordering, and a modest Sommerfeld coefficient (gamma) of 22.7 mJ mol-1 K-2 makes extensive Kondo hybridization unlikely. DC and AC magnetic susceptibility data suggest short-range magnetic order at similar to 5.2 and 7.6 K with no frequency dependence, ruling out canonical spin-glass behavior in this compound. Additionally, the magnetic susceptibility data do not contain any broad features that are typically associated with an intermediate valence state in Ce, suggesting either high-temperature valence fluctuation or a different mechanism of mixed valency. This work demonstrates that mixed-valent Ce inhibits magnetic ordering in CeFe2Ga8 and provides a broader framework for analyzing short-range spin interactions in Q1D intermetallics.

Chalcogenides-rich transition metal compounds host a rich landscape of emergent quantum phenomena that are intimately governed by their quasi-one-dimensional chemical-bonding frameworks and their response to external perturbations such as pressure. Here, we report a pressure-induced iso-symmetric structural transition in the quasi-one-dimensional compound CrNbSe_5, in which the electronic ground state is controlled not by symmetry breaking but by a continuous reorganization of local bonding interactions. Applied pressure reversibly tunes CrNbSe_5 between semiconducting and semimetallic states, enabling access to low- and high-carrier electronic regimes through direct modulation of metal-chalcogen bonding. High-pressure single-crystal X-ray diffraction directly resolves the evolution of Cr-Se and Nb-Se bond distances, coordination polyhedra, and connectivity, revealing a fully reversible semimetal-semiconductor-semimetal transition driven by gradual yet cooperative bond rearrangements within a preserved crystallographic symmetry. In contrast to chemical substitution, which irreversibly alters composition and introduces disorder, pressure acts as a clean, continuous control parameter that reshapes the bonding landscape without disrupting structural symmetry. These results establish CrNbSe_5 as a model system for electronically driven phase switching via tunable chemical bonding, highlighting iso-symmetric bond reorganization as a powerful design principle for pressure-controlled electronic and spintronic functionalities.

Cerium diantimonide (CeSb2) is a layered heavy-fermion Kondo lattice material that hosts complex magnetism and pressure-induced superconductivity. The interpretation of its in-plane anisotropy has remained unsettled due to structural twinning, which superimposes orthogonal magnetic responses. Here we combine controlled crystal growth with magnetization and rotational magnetometry to disentangle the effects of twinning. Nearly untwinned high-quality single crystals reveal the intrinsic in-plane anisotropy: The in-plane easy axis saturates at Measy(4 T) approximate to 1.8 & micro;B/Ce, while the in-plane hard axis magnetization is strongly suppressed, nearly linear, and comparable to the out-of-plane response. These results resolve long-standing discrepancies in reported magnetic measurements, in which in-plane metamagnetic transition fields and saturation magnetization varied significantly across previous studies. Growth experiments demonstrate that avoiding the proposed alpha 3 structural transition-through Sb-rich flux and slower cooling-systematically reduces twinning. However, powder x-ray diffraction and differential thermal analysis measurements show no clear evidence of a distinct 3 phase. Our results establish a consistent magnetic phase diagram and provide essential constraints for crystal-electric field models, enabling a clearer understanding of the interplay between anisotropic magnetism and unconventional superconductivity in CeSb2.

We report the discovery of a ternary compound, Eu0.8Pt6Al16.4. We determine its chemical and structural characteristics based on energy-dispersive X-ray spectroscopy as well as both powder and single-crystal X-ray diffraction, demonstrating that it crystallizes in a hexagonal structure type EuPt6Al17 with no reported structural analog. The temperature- and field-dependent magnetization, and temperature-dependent resistance measurements, reveal that the Eu2+ magnetic moments order antiferromagnetically below 2.8 K.

The appearance of spontaneous charge order in chemical systems is often associated with the emergence of novel, and useful, properties. Here we show through single crystal diffraction that the Eu ions in the mixed valent metal EuPd$_3$S$_4$ undergo long-range charge ordering at $T_{\mathrm{CO}} = 340 \mathrm{~K}$ resulting in simple cubic lattices of Eu$^{2+}$ ($J = 7/2$) and Eu$^{3+}$ ($J = 0$) ions. As only one of the two sublattices has a non-magnetic ground state, the charge order results in the emergence of remarkably simple G-type antiferromagnetic order at $T_{\mathrm{N}} = 2.85(6) \mathrm{~K}$, observed in magnetization, specific heat, and neutron diffraction. Application of a $0.3 \mathrm{~T}$ field is sufficient to induce a spin flop transition to a magnetically polarized, but still charge ordered, state. Density functional theory calculations show that this charge order also modifies the electronic degeneracies present in the material: without charge order, EuPd$_3$S$_4$ is an example of a double Dirac material containing 8-fold degenerate electronic states, greater than the maximum degeneracy of six possible in molecular systems. The symmetry reduction from charge order transmutes 8-fold double Dirac states into 4-fold Dirac states, a degeneracy that can be preserved even in the presence of the magnetic order. Our results show not only how charge order can be used to produce interesting magnetic lattices, but also how it can be used to engineer controlled degeneracies in electronic states.

Non-magnetic FeNb_3Se_10 has been demonstrated to be an insulator at ambient pressure through both theoretical calculations and experimental measurements and it does not host topological surface states. Here we show that on the application of pressure, FeNb_3Se_10 transitions to a metallic state at around 3.0 GPa. With a further increase in pressure, its resistivity becomes independent of both temperature and pressure. Its crystal structure is maintained to at least 4.4 GPa.