Thèse Engineering Multiferroicity At The 2D-Scale Coupling Polar And Magnetic Orders At The Atomic-Scale H/F

Doctorat.Gouv.Fr

Établissement : Université Paris-Saclay GS Sciences de l'ingénierie et des systèmes École doctorale : Interfaces : matériaux, systèmes, usages Laboratoire de recherche : [UMR 8580] Laboratoire Structures, Propriétés, Modélisation des Solides Direction de la thèse : Igor KORNEV Début de la thèse : 2026-10-01 Date limite de candidature : 2026-05-26T23:59:59 The quest for improved device performance has long driven advances in semiconductor technology through continuous miniaturization. As physical and economic limits emerge, research increasingly turns towards alternative strategies to enable new functionalities [1]. Two-dimensional (2D) materials represent a revolutionary class, inherently atomically thin, with unique electronic properties and compatible with silicon. In particular, the emergence of ferroelectricity (i.e., spontaneous polarization that can be switched by an electric field) in 2D monolayers, multilayers, and artificial structures such as twisted layers, offers further advantages, as ferroelectricity has traditionally been difficult to achieve in highly scaled materials.
2D ferroics are novel materials of great interest and still quite badly known. We will study 2D materials experimentally through a large range of structural, dielectric and magnetic measurements. We will use in-situ XRD, Raman spectroscopy, STEM, EELS/EDX, piezoforce microscopy, temperature and field-dependent dielectric measurements including ferroelectric polarisation, permittivity measurements...
Some of the most promising materials that we will study are CuInP2S6 [2, 3] which recently displayed strong ferroelectric polarization even at the scale of a few layers of materials and CuCrP2S6 which ferroelectricity could be coupled to a ferromagnetic order [4], making it a multiferroic material. Other promising 2D ferroelectric materials such as In2Se3 [5] will also be studied.
During this internship/PhD, the candidate will:
- Join a dynamic and internationally recognized team
- Study experimentally novel 2D materials in a joint laboratory between SPMS and Physics department of Arkansas, USA
- Contribute and participate to the work dissemination by writing papers and participating to international conferences and workshops 2D ferroics are novel materials of great interest and still quite badly known. We will study 2D materials experimentally through a large range of structural, dielectric and magnetic measurements. - Designing novel multiferroics based on chemical substitution of CuInP2S6 and CuCrP2S6 materials
- Structural, dielectric and magnetic characterisation of these 2D multiferroics at cryogenic temperatures (down to 4 K)
- DFT and effective hamiltonian modelling of these 2D multiferroics Experimental techniques: in-situ XRD, Raman spectroscopy, STEM, EELS/EDX, piezoforce microscopy, temperature and field-dependent dielectric measurements including ferroelectric polarisation measuremetns, permittivity measurements, magnetisation measurements...

Modelling techniques: DFT and effective hamiltonian