A5062397531- Iron-based superconductors research
- 2D Materials and Applications
- Crystallization and Solubility Studies
- Rare-earth and actinide compounds
- X-ray Diffraction in Crystallography
- Physics of Superconductivity and Magnetism
- Topological Materials and Phenomena
- Advanced Condensed Matter Physics
- Inorganic Chemistry and Materials
- Magnetic and transport properties of perovskites and related materials
- Chalcogenide Semiconductor Thin Films
- Superconductivity in MgB2 and Alloys
- MXene and MAX Phase Materials
- High Entropy Alloys Studies
- Graphene research and applications
- Electronic and Structural Properties of Oxides
- Machine Learning in Materials Science
- Organic and Molecular Conductors Research
- Perovskite Materials and Applications
- Metal and Thin Film Mechanics
- High-Temperature Coating Behaviors
- Quantum Dots Synthesis And Properties
- Advanced Thermoelectric Materials and Devices
- Molecular Junctions and Nanostructures
- Intermetallics and Advanced Alloy Properties
University of Geneva
2022-2025
University of Zurich
2015-2024
Princeton University
2012-2018
ETH Zurich
2010-2014
Electronic transport through exfoliated multilayers of CrSBr, a 2D semiconductor interest because its magnetic properties, is investigated. An extremely pronounced anisotropy manifesting itself in qualitative and quantitative differences all quantities measured along the in-plane b crystallographic directions found. In particular, qualitatively different dependence conductivities σa σb on temperature gate voltage, accompanied by orders magnitude their values (σb /σa ≈ 3 × 102 to 105 at low...
Significance High-entropy alloys are a new class of materials that consist several principal elements arranged on simple lattices. These structures stabilized by the high configurational entropy random mixing elements. Here, we show properties superconducting high-entropy alloy strongly related to electron count and transition temperatures these fall between those analogous crystalline amorphous materials. We find despite large degree randomness disorder in alloys, nevertheless dependent...
Significance High-entropy alloys (HEAs) are made from multiple transition-metal elements in equimolar or near-equimolar ratios. The HEAs arrange themselves randomly on the crystallographic positions of a simple lattice. In addition to their excellent mechanical properties, one HEA has been reported display superconductivity. this work, we report that Ta–Nb–Hf–Zr–Ti high-entropy alloy superconductor exhibits extraordinarily robust zero-resistance superconductivity under pressure up 190.6 GPa....
We report a facile colloidal synthesis of gallium (Ga) nanoparticles with the mean size tunable in range 12–46 nm and excellent distribution as small 7–8%. When stored under ambient conditions, Ga remain stable for months due to formation native passivating Ga-oxide layer (2–3 nm). The mechanism is elucidated using nuclear magnetic resonance spectroscopy molecular dynamics simulations. Size-dependent crystallization melting temperature 98–298 K are studied X-ray powder diffraction, specific...
In its orthorhombic T d polymorph, MoTe2 is a type-II Weyl semimetal, where the fermions emerge at boundary between electron and hole pockets. Non-saturating magnetoresistance superconductivity were also observed in d-MoTe2. Understanding d-MoTe2, which was proposed to be topologically non-trivial, of eminent interest. Here, we report high-pressure muon-spin rotation experiments probing temperature-dependent magnetic penetration depth A substantial increase superfluid density linear scaling...
We report on a new iron selenide superconductor with T C onset of 45K and the nominal composition Li x (C 5 H N) y Fe 2-z Se 2 , synthesized via intercalation dissolved alkaline metal in anhydrous pyridine at room temperature.This exhibits broad transition, reaching zero resistance 10K.Magnetization measurements reveal superconducting shielding fraction approximately 30%.Analogous phases intercalated Na, K Rb were also characterized.The transition temperature is clearly enhanced comparison...
Two-dimensional materials have significant potential for the development of new devices. Here we report electronic and structural properties $\beta$-GeSe, a previously unreported polymorph GeSe, with unique crystal structure that displays strong two-dimensional features. $\beta$-GeSe is made at high pressure temperature stable under ambient conditions. We compare it to its relatives $\alpha$-GeSe black phosphorus. The $\beta$ form GeSe boat conformation Ge-Se six-ring, while known $\alpha$...
Our experiments unambiguously establish 2H-MoTe 2 and 2H-MoSe as magnetic, moderate bandgap semiconductors.
We have synthesized previously unreported high-entropy alloys (HEAs) in the pentanary (ScZrNb)1–x[RhPd]x and hexanary (ScZrNbTa)1–x[RhPd]x systems. The materials CsCl-type structures mixed site occupancies. Both HEAs are type-II superconductors with strongly varying critical temperatures (Tc's) depending on valence electron count (VEC); Tc's increase monotonically decreasing VEC within each series, do not follow trends seen for either crystalline or amorphous transition metal...
The van-der-Waals material CrSBr stands out as a promising two-dimensional magnet. Here, we report on its detailed magnetic and structural characteristics. We evidence that it undergoes transition to an A-type antiferromagnetic state below TN ≈ 140 K with pronounced character, preceded by ferromagnetic correlations within the monolayers. Furthermore, unravel low-temperature hidden-order long-range magnetically-ordered state. find is associated slowing down of fluctuations, accompanied...
High-entropy alloys (HEAs) are a new class of materials constructed from multiple principal elements statistically arranged on simple crystallographic lattices. Due to the large amount disorder present, they excellent model systems for investigating properties intermediate between crystalline and amorphous states. Here we report effects systematic isoelectronic replacements, using Mo-Y, Mo-Sc, Cr-Sc mixtures, valence electron count 4 5 in body-centered cubic (BCC) Ta-Nb-Zr-Hf-Ti high-entropy...
The success of black phosphorus in fast electronic and photonic devices is hindered by its rapid degradation the presence oxygen. Orthorhombic tin selenide a representative group IV-VI binary compounds that are robust isoelectronic share same structure with phosphorus. We measure band SnSe find highly anisotropic valence bands form several valleys having dispersion within layers negligible across. This exactly desired for efficient thermoelectric generation where has shown great promise.
Strain is ubiquitous in solid-state materials, but despite its fundamental importance and technological relevance, leveraging externally applied strain to gain control over material properties still infancy. In particular, the diverse phase transitions topological states two-dimensional (2D) transition metal dichalcogenides (TMDs) remains an open challenge. Here, we exploit uniaxial stabilize long-debated structural ground state of 2D semimetal IrTe$_2$, which hidden unstrained samples....
Interlayer coupling is strongly implicated in the complex electronic properties of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>1</a:mn><a:mi>T</a:mi></a:mrow><a:mo>−</a:mo><a:msub><a:mi>TaS</a:mi><a:mn>2</a:mn></a:msub></a:math>. Uniaxial strain engineering offers a route to modify this order elucidate its interplay with structure and correlations. Here, we employ angle-resolved photoemission spectroscopy (ARPES) reveal effect uniaxial on <b:math...
The influence of carrier type on superconductivity has been an important issue for understanding both conventional and unconventional superconductors [1-7]. For elements that superconduct, it is known hole-carriers govern the transition main group metals [8-10]. role in are not normally conducting but can be converted to superconductors, however, remains unclear due lack experimental data. Here we report first in-situ high pressure Hall effect measurements single crystal black phosphorus,...
We report on the phase formation and superconducting properties in NbS$_2$ system. Specifically, we have performed a series of standardized solid-state syntheses this system, which allow us to establish comprehensive synthesis map for two polytypes 2H-NbS$_2$ 3R-NbS$_2$, respectively. show that identification by means X-ray diffraction is not always unambiguous. Our physical property measurements phase-pure sample 2H-NbS$_2$, mixed confirm earlier reports bulk superconductor 3R-NbS$_2$ above...
Abstract Motivated by the recent discovery of superconductivity in infinite-layer nickelate thin films, we report on a synthesis and magnetization study bulk samples parent compounds R NiO 2 ( = La, Pr, Nd). The frequency-dependent peaks alternating current magnetic susceptibility, along with remarkable memory effects, characterize spin-glass states. Furthermore, various phenomenological parameters via different spin glass models show strong similarity within these three as well other...
Compared to traditional superhard materials with high electron density and strong covalent bonds, alloy mainly composed of metallic bonding structures typically have great toughness lower hardness. Breaking through the limits is a preface long term topic, which significance value for improving comprehensive mechanical properties materials. Here, we report on discovery cubic semiconducting material Ti2Co large Vickers hardness Hvexp = 6.7 GPa low fracture KICexp =1.51 MPa m0.5. Unexpectedly,...
Layered delafossite-type compounds and related transition metal dichalcogenides, characterized by their triangular net structures, serve as prototypical systems for exploring the intricate interplay between crystal structure magnetic behavior. Herein, we report on discovery of compound K1–xCrSe2 (x ≈ 0.13), an incommensurately modulated phase. Single crystals this were grown first time using a K/Se self-flux. We find monoclinic with incommensurate modulation that can be rationalized 3 +...
TOC illustrates the polymorphic transformation of FeS 2 from marcasite to pyrite, highlighting energy barrier (Δ G ) associated with phase transition.
Gaining a deeper understanding of the interplay between charge density wave (CDW) order and superconductivity in transition metal dichalcogenides (TMDs), particularly within (4H/2H)-<a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mrow><a:mi>Nb</a:mi><a:mi>X</a:mi></a:mrow><a:mn>2</a:mn></a:msub><a:mo> </a:mo><a:mrow><a:mo>(</a:mo><a:mi>X</a:mi><a:mo>=</a:mo><a:mi>Se</a:mi></a:mrow></a:math> S) family, remains an open intriguing challenge. A systematic microscopic study across...
Isotypic compounds [Mg3(H2O)14][M(CN)6]2·4HMT·xH2O (HMT = hexamethylentetramine or urotropine) with M Fe, Cr and Co have been crystallized from aqueous solutions. The iron compound (M Fe) is most remarkable because it crystallizes distinctive thin, deep‐yellow crystal plates. structure of [Mg3(H2O)14][Fe(CN)6]2(C6H12N4)4(H2O)4.18 was solved refined by X‐ray single‐crystal diffraction, revealing the tetragonal space group P‾4c2, a 14.8156(5) Å, c 32.890(3) Å (Z 4). contains finite...
The physical properties and structural evolution of the 122-type solid solution BaNi2(Ge1-xPx)2 are reported. in-plane X-X (X = Ge1-xPx) dimer formation present in end member BaNi2Ge2, which results a transition to orthorhombic symmetry, is completely suppressed zero temperature on P substitution near x 0.7, dome-shape superconducting phase with maximum Tc 2.9 K emerges. Clear indications phonon softening enhanced electron-phonon coupling observed at composition instability. Our findings...
Complexes with purely pyridine-based macrocycles are rarely studied in photo(electro)catalysis. We synthesized and investigated macrocycles, which two 2,2'-bipyridine (bpy) units linked twice by cyano-methylene groups, to yield the basic tetradentate, bipyridine based ligand framework (pyr). The protons bridges were substituted obtain derivatives one (pyr-alk) or (pyr-alk2) alkyl-chains, respectively. present crystal structures of mono-pentylated cis-dibutylated ligands. corresponding Co(II)...