Publications associées à Impurity

Control of intermetallics in the interface in directed energy deposition of titanium on stainless steel 316L

Application of a single metal or alloy is often restricted by its properties from optimal combination of performance and cost. Therefore, there is a vast need of joining dissimilar metals for various applications in biomedical, aerospace, automobile and ma ...

EPFL2023

Tunneling processes through magnetic impurities on superconducting surfaces: Yu-Shiba-Rusinov states and the Josephson effect

Haonan Huang

Magnetic impurities generate a wealth of phenomena on surfaces. On metals, conducting electrons screen the magnetic moment giving rise to the Kondo effect. On superconductors, the Yu-Shiba-Rusinov (YSR) states emerge inside the superconducting gap due to t ...

EPFL2021

Long‐Lived Photocharges in Supramoelcular Polymers of Low‐Bandgap Chromophores

Andrzej Sienkiewicz, Holger Frauenrath, Daniel Görl, Regina Judith Hafner

Photoinduced charge separation in supramolecular aggregates of π‐conjugated molecules is a fundamental photophysical process, and a key criterion for the development of advanced organic electronics materials. Here, we report on the self‐assembly of novel l ...

2020

Emergent bound states and impurity pairs in chemically doped Shastry-Sutherland system

Frédéric Mila

Impurities often play a defining role in the ground states of frustrated quantum magnets. Studies of their effects are crucial in understanding of the phase diagram in these materials. SrCu2(BO3)(2), an experimental realization of the Shastry-Sutherland (S ...

Nature Research2019

Fast and ultrafast electron microscopies for skyrmions and plasmonics

Gabriele Berruto

In recent years, topology gained a central role in physics. We learnt that energetics could be often explained better by classes of objects defined by having qualitative differences. In today's jargon, we say they are topologically distinct. The process of ...

EPFL2019

Probing Alloy Formation Using Different Excitonic Species: The Particular Case of InGaN

Nicolas Grandjean, Raphaël Butté, Gordon Jens Callsen

Since the early 1960s, alloys are commonly grouped into two classes that feature either bound states in the band gap (I) or additional, nondiscrete band states (II). Consequently, one can observe either excitons bound to isoelectronic impurities or the typ ...

American Physical Society2019

Polarity-Controllable Devices and Circuits for Doping-Free 2D Electronics

Giovanni Vincenzo Resta

The growth of information technology has been sustained by the miniaturization of Complementary Metal-Oxide-Semiconductor (CMOS) Field-Effect Transistors (FETs), with the number of devices per unit area constantly increasing, as exemplified by Mooreâ s la ...

EPFL2019

Doping-free complementary inverter enabled by 2D WSe2 electrostatically-doped reconfigurable transistors

Giovanni De Micheli, Giovanni Vincenzo Resta, Pierre-Emmanuel Julien Marc Gaillardon

Amongst 2-dimensional (2D) semiconductors of the transition-metal di-chalcogenide (TMDC) family [1], tungsten diselenide (WSe2) has shown ambipolar behavior [2], [3] coupled with high carrier mobility [4] and CMOS-like devices have been experimentally demo ...

IEEE2018

Synthesis of Cyanine Polyelectrolytes and Anions for Organic Electronic Devices

Lei Wang

Many practical applications among organic electronic devices have been demonstrated over the last decades. They are considered as promising alternatives to inorganic semiconductor technologies due to the potential of cost-effective fabrication, excellent p ...

EPFL2017

Strength and fracture of silicon second-phase particles in aluminium casting alloys

Martin Guillermo Mueller

The mechanical behaviour of metallic materials that have a microstructure composed of a brittle phase embedded in a ductile matrix is dictated by a complex interplay of factors such as local phase properties, cohesive properties, geometrical characteristic ...

EPFL2017

Dynamics of Electronic and Ionic Charges in Cyanine Organic Semiconductor Devices

Sandra Christina Jenatsch

Organic semiconductor materials have been widely applied in optoelectronic devices to replace their inorganic counterparts and explore new fields of applications. Due to their high extinction coefficients, chemical tunability and solubility, cyanine dyes a ...

EPFL2017

Pressure-tuned Transport Properties of Novel Iron-based Superconductors and Topological Insulators

Andrea Pisoni

The majority of interactions in solids strongly depend on the interatomic distances. The application of pressure changes the lattice parameters and modifies the electronic and the phononic energy spectra of a material avoiding some of the undesirable effec ...

EPFL2016

Polarization charge as a reconfigurable quasi-dopant in ferroelectric thin films

Nava Setter, Alexander Tagantsev, Tomas Sluka, Arnaud Robert André Crassous

Impurity elements used as dopants are essential to semiconductor technology for controlling the concentration of charge carriers. Their location in the semiconductor crystal is determined during the fabrication process and remains fixed. However, another p ...

Nature Publishing Group2015

Quantum engineering of spin and anisotropy in magnetic molecular junctions

Klaus Kern, Markus Ternes

Single molecule magnets and single spin centres can be individually addressed when coupled to contacts forming an electrical junction. To control and engineer the magnetism of quantum devices, it is necessary to quantify how the structural and chemical env ...

Nature Publishing Group2015

Enhancing the Electrochemical and Electronic Performance of CVD-Grown Graphene by Minimizing Trace Metal Impurities

Klaus Kern, Kannan Balasubramanian

The presence of unwanted impurities in graphene is known to have a significant impact on its physical and chemical properties. Similar to carbon nanotubes, any trace metals present in graphene will affect the electrocatalytic properties of the material. He ...

Wiley-V C H Verlag Gmbh2014

Berry phase investigation of spin-S ladders

Frédéric Mila, Natalia Chepiga, Frédéric Alexis Michaud

We investigate the properties of antiferromagnetic spin-S ladders with the help of local Berry phases defined by imposing a twist on one or a few local bonds. In gapped systems with time-reversal symmetry, these Berry phases are quantized, hence able in pr ...

2013

Growth and optical, electrical and mechanical characterization of zinc oxide nanowires

Martial Duchamp

The topic of this dissertation is embedded into the new-born field of inorganic nanowires. The research was focused on zinc oxide (ZnO) nanowires, in particular, which besides posing fundamental questions in physics, promise broad range of applications. Zn ...

EPFL2010

Dzyaloshinskii-Moriya anisotropy and nonmagnetic impurities in the s=1/2 kagome system ZnCu3(OH)(6)Cl-2

Frédéric Mila, Bruce Normand, Salvatore Manmana, Ioannis Rousochatzakis

Motivated by recent nuclear magnetic resonance experiments on ZnCu3(OH)(6)Cl-2, we present an exact-diagonalization study of the combined effects of nonmagnetic impurities and Dzyaloshinskii-Moriya (DM) interactions in the s = 1/2 kagome antiferromagnet. T ...

2009

Kondo-effect of substitutional cobalt impurities at copper surfaces

Klaus Kern, Peter Wahl

The influence of the coordination on the Kondo temperature of a magnetic impurity at a noble metal surface and the line shape observed in low temperature scanning tunneling spectroscopy (STS) is investigated for single cobalt atoms adsorbed on and embedded ...

2009

Physical aspects of colossal dielectric constant material CaCu3Ti4O12 thin films

Paul Muralt

The underlying physical mechanism of the so-called colossal dielectric constant phenomenon in CaCu3Ti4O12 CCTO thin films were investigated by using semiconductor theories and methods. The semiconductivity of CCTO thin films originated from the acceptor de ...

2009