Publications associées à Orientation dependent emission properties of columnar quantum dash laser structures

Polarization-enhanced GaN Schottky barrier diodes: Ultra-thin InGaN for high breakdown voltage and low Ron

Elison de Nazareth Matioli, Alessandro Floriduz, Zheng Hao

In this work, we present a concept that leverages the strong piezoelectric polarization field in InGaN, which counteracts the external electric field at reverse bias. We show that despite the smaller InGaN band-gap and lower critical electric field, its st ...

2024

Surfactant behavior and limited incorporation of indium during in situ doping of GeSn grown by molecular beam epitaxy

Anna Fontcuberta i Morral, Andrea Giunto, Thomas Hagger, Louise Emma Webb

GeSn is a promising group-IV semiconductor material for on-chip Si photonics devices and high-mobility transistors. These devices require the use of doped GeSn regions, achieved preferably in situ during epitaxy. From the electronic valence point of view, ...

AMER PHYSICAL SOC2023

Multipolar Pseudochirality-Induced Optical Torque

Olivier Martin, Karim Achouri, Mintae Chung, Andrei Kiselev

It has been observed that achiral nanoparticles, such as flat helices, may be subjected to an optical torque even when illuminated by normally incident linearly polarized light. However, the origin of this fascinating phenomenon has so far remained mostly ...

Amer Chemical Soc2023

Magnetic structure of the two-dimensional XY antiferromagnet Sr2CoSi2O7 studied using single-crystal neutron diffraction

Bálint Náfrádi

We report a combined polarized and unpolarized neutron diffraction study on a multiferroic Sr2CoSi2O7 (SCSO) single crystal below and above the antiferromagnetic ordering temperature TN = 6.5 K. Unpolarized neutron diffraction measurements at 15 K confirm ...

AMER PHYSICAL SOC2023

Exploring Novel Modalities for Optical Diffraction Tomography

Amirhossein Saba Shirvan

In the past decade, optical diffraction tomography has gained a lot of attention for its ability to create label-free three-dimensional (3D) images of the refractive index distribution of biological samples using scattered fields measured through holograph ...

EPFL2023

GaN growth on ScAlMgO4 substrates via thermally-dewetted thin Al films

Elison de Nazareth Matioli, Alessandro Floriduz

In this note, we demonstrate the high-temperature growth of GaN on ScAlMgO4 substrates by metalorganic vapor phase epitaxy when a thin Al film is deposited ex situ on the ScAlMgO4 surface, prior to GaN growth. Mirror-like high-quality GaN epitaxial layers ...

IOP Publishing Ltd2022

Magneto-optical study of metamagnetic transitions in the antiferromagnetic phase of alpha-RuCl3

Zhe Wang

alpha-RuCl3 is a promising candidate material to realize the so far elusive quantum spin liquid ground state. However, at low temperatures, the coexistence of different exchange interactions couple the effective pseudospins into an antiferromagnetically zi ...

NATURE PORTFOLIO2022

Energy correlators of hadronically decaying electroweak bosons

Lorenzo Ricci, Marc Riembau Saperas

Energy correlators are field-theoretically clean and phenomenologically valuable probes of QCD dynamics. We explore the possibility of using the information encoded in the energy correlators of a hadronically decaying electroweak vector boson in order to e ...

American Physical Society2022

Extreme polarization-dependent supercontinuum generation in an uncladded silicon nitride waveguide

Camille Sophie Brès, Eirini Tagkoudi, Caroline Gaëlle Amiot

We experimentally demonstrate the generation of a short-wave infrared supercontinuum in an uncladded silicon nitride (Si3N4) waveguide with extreme polarization sensitivity at the pumping wavelength of 2.1 µm. The air-clad waveguide is specifically designe ...

2021

Sensing of Surface and Bulk Refractive Index Using Magnetophotonic Crystal with Hybrid Magneto-Optical Response

Serguei Sekatski

We propose an all-dielectric magneto-photonic crystal with a hybrid magneto-optical response that allows for the simultaneous measurements of the surface and bulk refractive index of the analyzed substance. The approach is based on two different spectral f ...

2021

van der Waals Epitaxy of Co10–xZn10–yMnx+y Thin Films: Chemical Composition Engineering and Magnetic Properties

Anna Fontcuberta i Morral, Jean-Baptiste Leran, Dirk Grundler, Ping Che, Simon Robert Escobar Steinvall, Andrea Mucchietto, Rajrupa Paul, Mohammad Hamdi

Topologically protected magnetic skyrmions have raised interest for future spintronics applications. One of the main challenges is the synthesis of room temperature skyrmion-hosting materials that are compatible with thin-film technology. We present an app ...

2021

Smooth GaN membranes by polarization-assisted electrochemical etching

Jean-François Carlin, Nicolas Grandjean, Joachim Armand Simonne Ciers

III-nitride membranes offer promising perspectives and improved device designs in photonics, electronics, and optomechanics. However, the removal of the growth substrate often leads to a rough membrane surface, which increases scattering losses in optical ...

AMER INST PHYSICS2021

Hidden bulk and surface effects in the spin polarization of the nodal-line semimetal ZrSiTe

Helmuth Berger, Marco Grioni, Arnaud Magrez, Oleg Yazyev, Alberto Crepaldi, Mauro Fanciulli, Gianmarco Gatti, Daniel Gosalbez Martinez, Silvan Dino Marcos Roth

Local inversion symmetry breaking in centrosymmetric materials can lead to large spin polarization of the electronic band structure in separate sectors of the unit cell. Here, the authors reveal such hidden spin polarisation in ZrSiTe using spin and angle ...

NATURE RESEARCH2021

Methods to Enhance Nuclear Magnetic Resonance Sensitivity at High Magnetic Field

Claudia Christina Zanella

MR is a well-established technique routinely used in preclinical and clinical studies. This thesis focussed on the improvement of sensitivity of different methods in MR. Hyperpolarized 129Xe gas is used for studying pulmonary disease or cerebral perfusion ...

EPFL2021

Fully spin-polarized bulk states in ferroelectric GeTe

Jan Hugo Dil, Mauro Fanciulli

By measuring the spin polarization of GeTe films as a function of light polarization we observed that the bulk states are fully spin polarized in the initial state, in strong contrast with observations for other systems with a strong spin-orbit interaction ...

2020

Magnetic structures and quadratic magnetoelectric effect in LiNiPO4 beyond 30 T

Ellen Fogh

Neutron diffraction with static and pulsed magnetic fields is used to directly probe the magnetic structures in LiNiPO4 up to 25 T and 42 T, respectively. By combining these results with magnetometry and electric polarization measurements under pulsed fiel ...

AMER PHYSICAL SOC2020

AlGaN/GaN Nanowires: from Electron Transport to RF Applications

Giovanni Santoruvo

Gallium Nitride (GaN) and all III-Nitride compounds have revolutionized the world with the development of the blue light emitting diode (LED). In addition, GaN-based epi-structures, such as AlGaN/GaN, enable the fabrication of high electron mobility transi ...

EPFL2020

Spin-dependent charge transfer at chiral electrodes probed by magnetic resonance

Jean-Philippe Ansermet, Christophe Roussel, Felix Blumenschein, Mika Antero Tamski

Chirality-induced spin selectivity is evidenced by exciting the spin resonance of radicals in an electrochemical cell where the working electrode is covered with a chiral self-assembled monolayer. Because the electron transfer to and from the paramagnetic ...

ROYAL SOC CHEMISTRY2020

Density control of GaN quantum dots on AlN single crystal

Nicolas Grandjean, Sebastian Pascal Tamariz Kaufmann, Gordon Jens Callsen

Full control over the density and emission properties of GaN quantum dots (QDs) should be feasible, provided that the growth proceeds in the Stranski-Krastanov (SK) growth mode. In this work, we derive the phase diagram for GaN QD formation on AlN by NH3-m ...

2019

GaN Quantum Dots for Room Temperature Excitonic Physics

Sebastian Pascal Tamariz Kaufmann

Quantum dots (QDs) are the result of quantum confinement in the three spatial directions, as such they exhibit remarkable properties, of which the most important is perhaps the absence of a continuum of states. The allowed energetic levels are discrete, si ...

EPFL2019