Séminaires PMMH

Séminaire PMMH - Site Jussieu

Séminaires café

Contact :
Benoit Semin
Sylvain Patinet
Etienne Reyssat
responsables-seminaires (arobase) pmmh.espci.fr

PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France

Tel : (33) 1 40 79 45 22

Comment venir ?

7 quai Saint Bernard, 75005 PARIS

Le séminaire hebdomadaire du laboratoire PMMH a lieu tous les vendredis à 11h, au premier étage Barre Cassan, campus Jussieu.


PhD in UPtoPARIS MSCA programme : Study of YBCO based SSPDs with specific investigation through global and local measurements (STM, SGM) of the microscopic mechanism leading to hotspot formation

Lieu de travail Paris - Ile-de-France - France

Intitulé du sujet

Study of YBCO based SSPDs with specific investigation through global and local measurements (STM, SGM) of the microscopic mechanism leading to hotspot formation

Champs scientifiques : Physique

Mots clés Scanning Tunneling Miscroscope, Superconducting Single Photon detector, Local electronic properties, superconducting to insulating transition

Description

Superconducting Single Photon Detector (SSPD) is a key technology for quantum communication or space-to-ground communications1. They consist of superconducting nanowires biased near their critical current. A (visible or near IR) photon absorption creates a hotspot that is converted into a measurable voltage pulse2. Although the microscopic picture of the particle-to-signal conversion is far from being understood, low-Tc SSPD are the best single photon detectors commercially available, in terms of quantum efficiency, jitter and dark counts. The main problem which prevents this technology to spread-out is the energy cost and complexity of 4K cryogenics. Making SSPD with High Temperature Superconducting materials (HTS SSPD) would allow working with currently available simplified energy efficient cryo-coolers working in the 60-80 K range. The aim of this PhD project is to fabricate YBCO based SSPD and to investigate, by mean of global and local (STM/AFM) measurements, the microscopic mechanism leading to hotspot formation, to optimize them. On this route, we will study NbN-based SSPDs as well, whose elaboration and characterization is fully controlled. We recently fabricated YBCO nano-meanders showing the highest aspect ratios ever reported so far with preserved superconducting properties3, and measured highly hysteretic I-V characteristics that are mandatory to reach single photon detection. We will reduce further the nanowire cross-section to approach the standard parameters for low-Tc SSPDs (4nm-thick, 100nm wide, 100µm long4), through the fruitful collaboration with J. Briatico at UMR Thales-CNRS5. The goal is to show the photo-response of YBCO nanowires at a photon level in the visible and near IR.
The core of the project is to address specific issues to improve SSPD performances : How the presence of strong supercurrents modifies the superconducting properties of the wire ? Are there “preferential locations” where absorption takes place ? How the film structure, inhomogeneities3, wire edges, bends affect… the detector efficiency ? Are there vortices, and do they influence the detection process ? Thanks to the unique UHV low-temperature Scanning Tunneling Microscopy/Atomic Force Microscope (STM/AFM) equipment installed at ESPCI Paris, we will study conventional low-Tc SSPD and HTS nano-meanders under biased current, to answer these questions, combining global transport measurements and local electronic properties such as superconducting current distribution and local density of states6. We will study the role of local topography and inhomogeneities on the detector efficiency and dark count rate. Using magnetic field, the presence and the distribution of vortices under current biasing will be studied. The tip will be used as pulse current source to inject high-energy quasi-particles to trigger the detection event. [1] Nature Photon. (2009) [2] SUST (2012) [3]. APL (1999) [4] SUST (2018) [5] Begon-Lours, thesis (2017) [6] Jalabert et al Private Comm.

3i apsect of the project

Intersectoriality

This project aims at studying the fundamental issues related to the study of the parameters affecting the global and local phase coherence of disordered superconducting thin films and nanowires to give clues to the microscopic mechanism below the formation of the hotspot.
Moreover it has a strong industrial impact, indeed SSPDs overcome in many ways their semiconductors based counterparts and are commercially available. Some tremendous advantages have been reported recently such as high quantum efficiency ( 93% at l 1.54μm ), high operating frequency ( 1 GHz), low intrinsic dark count rate ( 0.1cps ), low jitter ( 18ns full width at half maximum) and broad spectral range (from visible to mid-infrared). Being able to identify the microscopic mechanism responsible for the detection of the photon, will allow improving this available low Tc technology and give better understanding of superconducting properties in High Tc nanowire to make the first high Tc SSPDs working upon 40K
Then this project is at the very early stage of thinking regarding potential applications for society and will not for instance drive the development of a new industry in France in near future.

Interdisciplinarity

The project will involve several foreign collaborators mostly in European institutions. On one hand, the QuantumSpec group has a long-standing collaboration with IMS-KIT (Institute of Micro- and Nanoelectronic Systems, Karlsruhe Institute of Technology) in particular they supply high quality NbN ultra-thin films. This collaboration has been strengthened by the ANR SUPERTRIPES grants fot both collaborators. On the other hand the PHASME group has established a long-standing collaboration with a group of theoreticians at La Sapienza University in Roma (Italy). Around ten co-authored scientific articles have been produced over the past years through this fruitful collaboration.

International mobility

The project will involve several foreign collaborators mostly in European institutions. On one hand, the QuantumSpec group has a long-standing collaboration with IMS-KIT (Institute of Micro- and Nanoelectronic Systems, Karlsruhe Institute of Technology) in particular they supply high quality NbN ultra-thin films. This collaboration has been strengthened by the ANR SUPERTRIPES grants for both collaborators. On the other hand the PHASME group has established a long-standing collaboration with a group of theoreticians at La Sapienza University in Roma (Italy). Around ten co-authored scientific articles have been produced over the past years through this fruitful collaboration.
Nature du financement

Financement public/privé
Précisions sur le financement
MSCA Cofund UPtoPARIS

Présentation établissement et labo d'accueil

ESPCI Paris

UMR7636 Physics & Materials

Description of the research Unit/subunit

The project will take place in the LPEM (UMR8213) in both QuantumSpec (D. Roditchev, S. Pons, S. Vlaic) and Phasme Group (C. Feuillet-Palma, J. Lesueur and N. Bergeal).
The QuantumSpec group is headed by D. Roditchev, who recently moved from INSP to the LPEM in ESPCI-Paris, an assistant professor S. Vlaic and a CNRS researcher S. Pons.
D. Roditchev is internationally recognized for his expertise in building and operating low temperature STM and has built the 300mK apparatus used in INSP. He is a worldwide expert recognized internationally in superconductivity.
The Phasme group has been studying superconductors at a meso and nanoscale for many years, from High-Tc cuprates to 2-DEG at oxide interfaces, from basic research to applications. The group made essential contributions to understand the fundamental properties of superconducting cuprates, and at the same time, developed a new technology to make HTc nanowires and Josephson junctions which are used in various functional circuits (SQUID, SQUIFS, THz mixers and single photon detectors).
The complementarity of the teams brings the full span of skills necessary for the successful completion of the project.

Name of the supervisor
Dimitri Roditchev (Dimitri.Roditchev (arobase) espci.fr)

Name of the co-supervisor
Cheryl Feuillet-Palma (cheryl.palma (arobase) espci.fr)

Site web :

https://www.upto.paris/

Profil du candidat

We are looking for motivated applicants with an excellent academic background in particular in quantum physics and solid state physics. The Phd applicant should be motivated by experimental physic and able to work independently. He/She should have good communication skills and be proficient in spoken and written English.
Although not mandatory, previous experiences in the following fields will be positively considered :

scanning tunneling microscope
atomic force microscope
ultra-high vacuum
electronic transport measurements
cryogenic systems operation
micro and nanofabrication

Date limite de candidature

31/03/2019

Applications must be submitted on the UPtoPARIS website : https://www.upto.paris/
More information is available in the "How to apply" section of the website

!! BEGINNING OF THESIS BETWEEN MARCH AND SEPTEMBER 2019 !!

Haut de page







Séminaires récents  (6)

  • Séminaire PMMH- Elisabeth Guazzelli (MSC)
    Vendredi 7 février 11:00-12:00 - Salle réunion PMMH 1
    Particle motion in vortical flows
    In many natural phenomena or industrial applications, heavy particles are transported in complex flows. The flow structures may happen to promote the stirring and dispersion of the particles. But the opposite can also take place and the flow configuration may contribute to the focussing and accumulation of (...)
  • Séminaire PMMH- Dwight Barkley (University of Warwick)
    Vendredi 31 janvier 11:00-12:00 - Salle réunion PMMH 1
    A fluid mechanic's analysis of the tea-cup singularity
    In 1926 Einstein published a short paper explaining the meandering of rivers. He famously began the paper by discussing the secondary flow generated in a stirred tea cup — the flow now widely known to be responsible for the collection of tea leaves at the center of a stirred cup of tea. In 2014, Luo and Hou (...)
  • Séminaire PMMH- Kristina Davitt (ENS)
    Vendredi 24 janvier 11:00-12:00 - Salle réunion PMMH 1
    Wetting hysteresis and dynamics : interpreting dissipation mechanisms at the contact line
    A liquid moving over a solid substrate is an everyday occurrence, and the hysteresis and dynamics of the three-phase contact line have been measured in innumerable experiments over the years. In addition, the ingredients needed to describe the phenomenon are known : in the most basic picture, there is viscous (...)
  • Séminaire PMMH - Doron Grossman (Collège de France)
    Vendredi 17 janvier 11:00-12:00 - Salle réunion PMMH 1
    From Molecules to Helical Ribbons - Shape and Shape Fluctuations
    * Self assembly of molecules into supramolecular structures is an important process through which non trivial structures are formed in nano-metric scale. The resulting structure depends on chemical and physical principles that govern the process, and may be sensitive to the exact conditions in which they are (...)
  • Séminaire PMMH Nicolas Triantafyllidis (LMS polytechnique)
    Vendredi 10 janvier 11:00-12:00 - Salle réunion PMMH 1
    STABILITY PROBLEMS IN MECHANICS : MULTIPHYSICS AND MULTISCALE ASPECTS (A MECANICIAN'S PERSPECTIVE…)
    Stability is a fascinating topic in solid mechanics that has its roots in the celebrated Euler column buckling problem, which first appeared in 1744. Over the years advances in technology have led to the study of ever more complicated structures first in civil and subsequently in mechanical engineering applications. (...)
  • Séminaire PMMH - Jean-Philippe Bouchaud
    Vendredi 20 décembre 2019 11:00-12:00 - Salle réunion PMMH 1
    Crises et phénomènes socio-économiques collectifs
    Comme l'écrivait P. W. Anderson en 1972 dans « More is different », le comportement de grandes assemblées d'individus ne peut pas être compris à partir de l'extrapolation du comportement d'individus isolés. Au contraire, des comportements complètement nouveaux, parfois spectaculaires et difficiles à anticiper, peuvent (...)

Instructions générales pour les conférenciers

Le public du séminaire est très hétérogène (rien qu’au PMMH nous travaillons sur des thématiques très diverses, mécanique des fluides, des milieux granulaires, des solides, physique statistique, physique du mouillage, micro-fluidique, biophysique,...) l’objectif est donc de ne pas faire un séminaire trop spécialiste : au moins la première moitié du séminaire à un niveau accessible pour celui qui ne connaît rien sur le sujet.

Le séminaire a lieu à 11h. rendez-vous 15 minutes avant pour installer et tester la projection.

Le séminaire dure environ 45 minutes pour laisser un peu de temps pour discuter à la fin.

Haut de page



Informations Pratiques

Laboratoire : 01 40 79 45 22
Directeur : Damien Vandembroucq
Codirecteur : Philippe Petitjeans
Administratrice : Frédérique Auger (01 40 79 45 22)
Gestionnaire : Claudette Barez (01 40 79 58 53)
Courriel : dir (arobase) pmmh.espci.fr

Nous rendre visite