Research Interests

Mesoscale and Nanoscale Physics
Ballistic conduction & transport of electrons, quantum Hall effect, spin-orbit interactions, 2DEG, graphene,nanofabrication.
Strongly correlated electrons
Heavy fermions, topological insulators, Berry phase, Moiré superlattices, metal-insulator transitions.
Low temperatures
Superconductivity, superfluidity, phonons at low temperatures, cryogenics, operation of a dilution refrigerator.

Main skills

Solid State Physics & Chemistry and Applications
  • Cryogenics, dilution refrigerator, magnetoresistance measurements
  • Lock-in measurements, signal processing & filtering
  • Nanofabrication, graphene & 2D materials devices
  • Electron microscopy, synchrotron X-ray techniques, X-ray diffraction, X-ray photoemission spectroscopy, IR spectroscopy
  • Theory of scattering + diffraction, in-depth understanding of waves crystalline materials + quantum phenomena.
  • Showcase results, content marketing, public relations


Ph.D. in Physics Manchester, UK. grad. exp. 2022.
  • School of Physics and Astronomy, The University of Manchester
  • Van der Waals Heterostructures using combinations of graphene, and other 2D materials
  • Supervisor: Pr Andre K. Geim;
  • Scholarship: G1,
  • Awards: A1
  • Publications: U1, C1,
  • Talks: T1, T2.
Visiting student Researcher Menlo Park, CA, USA. 2018.
  • SLAC National Accelerator Laboratory
  • Understand the origin of octahedral tilt in hybrid perovskites
  • Advisor: Dr Michael F. Toney
  • Grant: G2,
  • Publications: J1, C2, C3,
  • Talk: T3.
M.Sc. in Chemical Physics Paris, France. grad. 2018
  • ESPCI Paris: École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris
  • Diplôme d'ingénieur
B.Sc. in Physics Paris, France. grad. 2016
  • Sorbonne Université - Université Pierre-et-Marie-Curie
  • Minor: Chemistry


Graduate Teaching Assistant Manchester, UK. 2018-2019
& 2019-2020
  • Introduction to Programming for Physicists
  • School of Physics and Astronomy, The University of Manchester, 2nd year undergraduate (Python & C++ in 2018-2019, Python only in 2019-2020)
  • Assessed and advised the students on the programming course
  • Proposed student pastoral support
  • Marking of assignments
  • 7 hours per week
Graduate Teaching Assistant Paris, France. 2016-2017
  • Mathematics (Algebra & Analysis)
  • Lycée Saint Louis, 1st year undergraduate
  • Prepared students attending “Classes Préparatoires aux Grandes Écoles” for the Mathematics oral exam to the French Grandes Écoles for scientific studies.
  • Provided pastoral support per group of 3
  • Assessed
  • 2 hours per week

Leadership and activities

Cohort Representative 2018-.
  • ESPCI Alumni Association
  • Organisation of the graduation ceremony and party.
  • Census of the graduates.
  • Organise cohort meetups (ski weekend, weekend in Normandy, etc.)
  • Relay ESPCI Alumni Association's mutual aid in the class of 2018.
  • Promote ESPCI Alumni's events.
Communications and Public Relations Officer 2016.
  • ESPCI Student's Sport Union
  • Set up communications and growth strategy.
  • Designed visual identity.
  • Mapped out, promoted and implemented the communications framework & platforms strategy.
  • Managed digital communications channels.
  • Designed and fundraised for the sport jerseys.
  • Negociated sponsorships.
  • Managed public & press relations.
  • Results: ×3 growth in membership, ×4 growth in sponsorship revenues.
Communications Officer 2009-2012.
  • Jappix, web-based communication platform
  • Co-founded the open-source program.
  • Managed UI design.
  • Developped a communications and marketing strategy.
  • Results: 100k+ downloads, 50k+ users on
Event organisation
  • ESPCI Gala Dinner, 2018, Communications Officer.
  • ESPCI Gala Dinner, 2016, Vice President.
  • Journée de l'Informatique Libre (Free Software Day) 2011, Conference Program committee officer.

Professional Experience

R&D Intern Lyons + Chambéry, France. 2017
  • Synthesised + characterised nanocharged acrylic adhesives for the encapsulation of optoelectronic devices.
  • Enhanced the barrier properties towads gases and water with proper dispersion of nanocharges.
  • Carried out compatibility tests of the produced adhesives to Organic and Perovskite Solar Cells.
  • Synthesised solgel zirconium phosphate nanoplatelets, and functionnalised their surfaces.
  • Advisors: Dr Stéphane Cros (CEA), Dr Frédéric Chaput (ENS) and Dr Manuel Hidalgo (Arkema)
  • Talks: T4, T5.


Preprints, currently under review
  1. Electronic phase separation in topological surface states of rhombohedral graphite
    Yanmeng Shi, Shuigang Xu, Yaping Yang, Sergey Slizovskiy, Sergei V. Morozov, Seok-Kyun Son, Servet Ozdemir, Ciaran Mullan, Julien Barrier, Jun Yin, Alexei I. Berdyugin, Benjamin A. Piot, Takashi Taniguchi, Kenji Watanabe, Vladimir I. Fal'ko, Kostya S. Novoselov, Andre K. Geim and Artem Mishchenko.
Peer-reviewed papers
  1. Structural origins of light-induced phase segregation in organic-inorganic halide perovskite photovoltaic materials
    Rachel E. Beal, Nanna Zhou Hagström, Julien Barrier, Aryeh Gold-Parker Rohit Prasanna, Kevin A. Bush, Donata Passarello, Laura T. Schelhas, Karsten Brüning, Christopher J. Tassone, Hans-Georg Steinrück, Michael D. McGehee, Michael F. Toney, and Ana Flávia Nogueira.
    Matter. Volume 02. Issue 01. pages 207-219. 8 January 2020
    DOI: 10.1016/j.matt.2019.11.001
Peer-reviewed conference abstracts
  1. Direct observation of Brown-Zak mini-bands in graphene superlattices Helsinki, Finland. 24 September 2019
    Julien Barrier, Alexey I. Berdyugin, Piranavan Kumaravadivel, Takashi Taniguchi, Kenji Watanabe, Vladimir I. Fal’ko and Andre K. Geim.
    Graphene Week, Graphene Flagship, poster.
  2. Structural and mechanistic origins of light-induced phase segregation in organic- inorganic halide perovskite photovoltaic materials Birmingham, UK. 8 July 2019
    Michael F. Toney, Rachel E. Beal, Julien Barrier, Hans-Georg Steinrück, Michael D. McGehee and Ana Flávia Nogueira.
    RSC MC 14, oral communication.
  3. Tetragonal to Cubic Phase Transition in FA1-xCsxPb(I1-yBry)3: Temperature Dependance and Impact on Band Gap Boston, MA, USA. 30 Nov 2018
    Julien Barrier, Aryeh Gold-Parker, Eli Wolf, Rachel E. Beal, Michael D. McGehee and Michael F. Toney
    MRS Fall 2018, oral communication.

Workshops & Schools

  1. Participation in Moiré in Paris, Laboratoire de Physique, ENS Paris, PSL Research University, 3-4 June 2019;
  2. UC Mesoscale Summer School, University of California at Irvine, CA, USA. August 2018.

Grants, Awards & Scholarships

  1. Ingénieur du futur dans la catégorie Recherche (Engineer of the future in research) December 2019
    L'Usine Nouvelle, UTC & Sorbonne Université
Grants & Scholarships
  1. Doctoral Training Partnership Bursary September 2018
    (wrote the proposal)
  2. Mobility Scholarship for Visiting Student Researcher at SLAC March 2018
    Fonds ESPCI Paris
    (wrote the proposal)

Invited Talks

  1. Novel quantum phenomena in graphene, Trophée des Ingénieurs du Futur, Paris, 3 December 2019;
  2. Quantum electrons to the naked eye, Pint of Science, Manchester, 21 May 2019;
  3. Phase transition in mixed halide perovskites, impact on band-gap, Stanford Synchrotron Radiation Lightsource, Menlo Park, 24 August 2018;
  4. Encapsulation of flexible electronic devices, Laboratoire de Chimie - ENS de Lyon, Lyons, 22 December 2018;
  5. Gas barrier adhesives for encapsulation of organic and perovskite solar cells, LMPO CEA Liten, Chambéry, 19 December 2017;
  6. Jappix, free social network, Université de Genève, Geneva, 10 July 2012;
  7. Le web social, ISEN, Toulon, 28 April 2012;
  8. Réseaux sociaux libres, Unistra, Strasbourg, 12 July 2011;
  9. Jappix, réseau social libre, FOL83, Toulon, 15 January 2011;
  10. Jappix, un micro-réseau social libre, Polytech Nice, Sophia-Antipolis, 27 November 2010;
  11. Jappix, ENSEIRB, Bordeaux, 9 July 2010.


  • Thophée des ingénieurs du futur : lauréats et nommés dans la catégorie Recherche, 23 December 2019. Reported by Manuel Moragues, Industrie & Technologies. France.
  • Julien Barrier, l'électron libre, 5 December 2019. Reported by Olivier James, L'Usine Nouvelle. France.
  • Découvrez le monde le l’informatique libre. 27 April 2012. Reported by Myriam Tricocci Robert, Metro Toulon. France.
  • Informatique : la liberté à portée de clic. 14 January 2011. Reported by Thierry Turpin, La Marseillaise. France.
  • Actualités locales, 31 August 2010. Reported by Jacky Laurent, Var Matin La Seyne-sur-Mer. France.
  • Cyber Culture. 27 Septembre 2014, 2:00 PM, Radio Ici & Maintenant FM 95.2 MHz, Paris, France. Produced by Olivier Piquepé. 3h30’.
  • Jappix. La Voix du Libre, 13 July 2011, 9:30 AM, Radio RMLL (web), Québec, Canada. Produced by Yannick Pavard. 19’.
  • Morning News, 10 January 2010, 7:30 AM, France Bleu Provence FM 109.2 MHz, Toulon, France. 4’
  • “Nous voulons garantir les libertés des utilisateurs.” 29 April 2012. Reported by David Latour. Var Matin Toulon. France.
  • Jappix, interview de Julien Barrier Dossier spécial Tchat, web & messagerie, October 2010. Reported by Aline Hof. Linux Pratique Essentiel. Issue 16. pages 5–7. France.


  • Born in January 1994 in Paris, France.
  • Hobbies comprise sailing, skiing, hiking, bike riding & cooking.
  • Current address:
    Schuster Building 2.23
    School of Physics and Astronomy
    The University of Manchester
    Manchester M13 9PL, UK.