A5081656992- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Iron-based superconductors research
- Rare-earth and actinide compounds
- Surface and Thin Film Phenomena
- Intellectual Capital and Performance Analysis
- Corporate Taxation and Avoidance
- Quantum and electron transport phenomena
- Hydraulic flow and structures
- Magnetic and transport properties of perovskites and related materials
- Oil and Gas Production Techniques
- Metal and Thin Film Mechanics
- 2D Materials and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Condensed Matter Physics
- Graphene research and applications
- Advanced Chemical Physics Studies
- Advanced Physical and Chemical Molecular Interactions
- Cavitation Phenomena in Pumps
- Quantum, superfluid, helium dynamics
- Superconductivity in MgB2 and Alloys
- Molecular Junctions and Nanostructures
- Superconducting Materials and Applications
- Multiferroics and related materials
Universidad Autónoma de Madrid
2019-2025
CrGeTe3 (CGT) is a semiconducting vdW ferromagnet shown to possess magnetism down two-layer thick sample. Although CGT one of the leading candidates for spintronics devices, comprehensive analysis thickness dependent magnetization currently lacking. In this work, we employ scanning SQUID-on-tip (SOT) microscopy resolve magnetic properties exfoliated flakes at 4.2 K. Combining transport measurements CGT/NbSe2 samples with SOT images, present texture and hysteretic CGT, thereby matching global...
Abstract Two-dimensional electronic states at surfaces are often observed in simple wide-band metals such as Cu or Ag (refs. 1–4 ). Confinement by closed geometries the nanometre scale, surface terraces, leads to quantized energy levels formed from band, stark contrast continuous dependence of bulk electron bands 2,5–10 . Their energy-level separation is typically hundreds meV 3,6,11 In a distinct class materials, strong correlations lead so-called heavy fermions with strongly reduced...
The orthorhombic compound ${\mathrm{AuSn}}_{4}$ is compositionally similar to the Dirac node arc semimetal ${\mathrm{PtSn}}_{4}$. is, contrary ${\mathrm{PtSn}}_{4}$, superconducting with a critical temperature of ${T}_{c}=2.35$ K. Recent measurements present indications for quasi-two-dimensional behavior in ${\mathrm{AuSn}}_{4}$. Here we density states and band structure through scanning tunneling microscopy angular resolved photoemission spectroscopy (ARPES). gap values different portions...
Some single-crystalline materials present an electrical resistivity which decreases between room temperature and low temperatures at zero magnetic field as in a good metal switches to nearly semiconductinglike behavior with the application of field. Often, this is accompanied by huge nonsaturating linear magnetoresistance remains difficult explain. Here we systematic study single-crystal $\gamma$-PtBi$_2$. We observe that angle crystalline $c$ axis fundamentally changes magnetoresistance,...
The electronic bandstructure of Au$_2$Pb has a Dirac cone which gaps when undergoing structural transition into low temperature superconducting phase. This suggests that the phase ($T_c=1.1$ K) might hold topological properties at surface. Here we make Scanning Tunneling Microscopy experiments on surface Au$_2$Pb. We measure gap and find sizeable density states Fermi level. discuss possible origins for this finding in terms superconductivity induced states.
A Scanning Tunneling Microscope (STM) is one of the most important scanning probe tools available to study and manipulate matter at nanoscale. In a STM, tip scanned on top surface with separation few Å. Often, tunneling current between sample maintained constant by modifying distance apex through feedback mechanism acting piezoelectric transducer. This produces very detailed images electronic properties surface. The nearly always made using digital processing circuit separate from user...
Abstract Bound states in superconductors are expected to exhibit a spatially resolved electron-hole asymmetry which is the hallmark of their quantum nature. This manifests as oscillations at Fermi wavelength, usually tiny and thus washed out by thermal broadening or scattering defects. Here we demonstrate theoretically confirm experimentally that, when coupled magnetic impurities, bound vortex core an emergent axial on much longer scale, set coherence length. We study vortices 2H-NbSe 2 1.8...
Liquid Helium is used widely, from hospitals to characterization of materials at low temperatures. Many experiments temperatures require liquid Helium, particularly when vibration isolation precludes the use cryocoolers and one needs cool heavy equipment such as superconducting coils. Here we describe methods simplify operations required by eliminating high pressure bottles, avoiding blockage improving heating cooling rates. First show a simple very cost method transfer transport container...
We present magnetoresistivity measurements in high-quality single crystals of the Nowotny chimney ladder compound ${\mathrm{Ru}}_{2}{\mathrm{Sn}}_{3}$. find a linear and nonsaturating magnetoresistance up to 20 T. The changes with magnetic field orientation at small fields, from positive negative curvature. Above 5 T, shows no sign saturation T for any measured angle. shape anisotropy remains when increasing temperature Kohler's rule is obeyed. associate Fermi surface hot spots, possibly...
We study the electronic densities of states (DOS) strongly disordered superconducting thin films TiN. find, using Scanning Tunneling Microscopy (STM) that DOS decreases towards Fermi level in normal phase obtained by applying magnetic fields. The shows spatial fluctuations whose length scale is related to energy dependent and similar phases. This suggests Coulomb interactions lead a spatially varying superconductor.
The magnetoresistance (MR) of iron pnictide superconductors is often dominated by electron-electron correlations and deviates from theH2or saturating behaviors expected for uncorrelated metals. Contrary to similar Fe-based systems, the superconductor LaRu2P2(Tc= 4 K) shows no enhancement correlations. Here we report a non-saturating MR deviating in LaRu2P2. We present results single crystals LaRu2P2, where observe followingH1.3up 22 T. discuss our result comparing bandstructure LaRu2P2with...
The orthorhombic compound AuSn4 is compositionally similar to the Dirac node arc semimetal PtSn$_4$. AuSn$_4$ is, contrary PtSn$_4$, superconducting with a critical temperature of T$_c$ = 2.35 K. Recent measurements present indications for quasi two-dimensional behavior in AuSn$_4$. Here we density states and band structure through Scanning Tunneling Microscopy (STM) Angular Resolved Photoemission Spectroscopy (ARPES). gap values different portions Fermi surface are spread around Δ0 0.4 meV,...
High critical temperature superconductivity often occurs in systems where an antiferromagnetic order is brought near $T=0K$ by slightly modifying pressure or doping. CaKFe$_4$As$_4$ a superconducting, stoichiometric iron pnictide compound showing optimal superconducting with $T_c$ as large $38$ K. Doping Ni induces decrease and the onset of spin-vortex order, which consists spins pointing inwards to outwards from alternating As sites on diagonals in-plane square Fe lattice. Here we study...
Moir\'e patterns can lead to fundamentally new electronic behavior when formed between two atomic lattices slightly shifted with respect each other. A solid is however not just characterized by the lattice, but also charge or magnetic excitations that do need be commensurate lattice. This raises question if one obtain a moir\'e combining periodic modulations and Here we report on discovery of one-dimensional density wave (1D-CDW) which pattern lattice hot spot for scattering in bandstructure...
The ultimate spatial limit to establish a Josephson coupling between two superconducting electrodes is an atomic-scale vacuum tunneling junction. effect in such ultrasmall junctions has been widely used study materials, providing powerful probe of the variations superfluid density. Furthermore, studies supercurrent and charging effects unveiled new, frequency dependent, switching dynamics thermal processes emerging due small size junctions. However, Cooper pair current magnitude was...
Este trabajo desarrolla un algoritmo computacional, para la realización de selección y diseño las dimensiones principales del rodete, diferentes turbinas hidráulicas por redes neuronales una mini central entre 50 kw a 4000 kw, haciendo uso técnicas numerosas experiencias práctica experimental laboratorio expertos, en materias tan específicas como estas acción reacción, complementando con red neuronal artificial ecuaciones cálculo tabuladas cuadros estadísticos.Dicha realiza el Sistema...
The magnetoresistance of iron pnictide superconductors is often dominated by electron-electron correlations and deviates from the H$^2$ or saturating behaviors expected for uncorrelated metals. Contrary to similar Fe-based systems, superconductor LaRu$_2$P$_2$ (T$_c$ = 4 K) shows no enhancement correlations. Here we report a non-saturating deviating in LaRu$_2$P$_2$. We have grown characterized high quality single crystals measured following H$^{1.3}$ up 22 T. discuss our result comparing...
Electrons can form a two-dimensional electron gas at metal surfaces, where lateral confinement leads to quantum-well states. Such states have been observed for highly itinerant electrons, but it remains an open question whether be formed from strongly correlated electrons. Here we study atomically flat terraces on surfaces of the heavy-fermion superconductor URu$_2$Si$_2$ using millikelvin scanning tunneling spectroscopy. We observe heavy fermions (2DHF) with effective mass 17 times free...