Nanolamellar & 2D Materials

The M_n+1AX_n phases, or “MAX” phases, are nano-laminates, where M is an early transition metal, A belongs to groups 13-16, and X is either C or N. They were discovered some decades ago. MAX phases crystallize in a hexagonal structure and uniquely combine both metallic and ceramic characteristics. In the research line Nanolamellar & 2D Materials, we grow single crystals of MAX phases using high temperature solution growth [1] and determine their physical properties, focusing on the anisotropies expected from their nano-lamellar structure. To cite but a few examples, in collaboration with our various partners, we have measured magneto-transport [2], band structure [3] or phonon dispersion [4] anisotropies of MAX phase single crystals. We do not limit ourselves to nanolamellar carbides, but we have also started to develop activities on nanolamellar borides [5] and rare-earth nanolaminates [6].

We also use MAX and MAB phase crystals to study their exfoliation kinetics [7] and to produce two-dimensional (2D) materials as MXenes using wet chemistry or molten salt assisted synthesis. The library of the synthesized materials includes Ti₃C₂T_z, Ti₂CT_z, Ti₂C_0.5N_0.5T_z, Ti₃CNT_z, V₂CT_z, Nb₂CT_z, just to name a few. We explore the physical characteristics of synthesized 2D materials, in particular transport properties, and their integration into various applications belonging to the fields of sensing [8], photovoltaics [9], and energy [10].

We conduct our research through a rich collaborative network, involving Institut Néel (France), ESRF (France), Université Catholique de Louvain (Belgium), Drexel University (USA), Nagoya University (Japan), Institut Pprime (France) and The Institute of Structure of Matter (Italy).

[1] L. Shi et al. Acta Materialia 83, 304 (2015)
Synthesis of Single Crystals of V₂AlC Phase by High-Temperature Solution Growth and Slow Cooling Technique

[2] T. Ouisse et al. Physical Review B 92, 045133 (2015)
Magnetotransport Properties of Nearly-Free Electrons in 2D Hexagonal Metals and Application to the M_n+1AX_n Phases

[3] D. Pinek et al. Physical Review B 100, 075144 (2019)
Unified Description of the Electronic Structure of M₂AC Nanolamellar Carbides

[4] A. Champagne et al. Materials Research Letters 6, 378 (2018)
Phonon Dispersion Curves in Cr₂AlC Single-Crystals

[5] L. Verger et al. Journal of Applied Physics 124, 205108 (2018)
Anisotropic Thermal Expansions of Select Layered Ternary Transition Metal Borides: MoAlB, Cr₂AlB₂, Mn₂AlB₂, and Fe₂AlB₂

[6] Q. Tao et al. Physical Review Materials 2, 114401 (2018)
Rare-Earth (RE) Nanolaminates Mo₄RE₄Al₇C₄ Featturing Ferromagnetism and Mixed-Valence States

[7] Y. Kim et al. RSC Advances 10, 25266-25274 (2020)
Elementary Processes Governing V₂AlC Chemical Etching in HF

[8] H. Pazniak et al. Advanced Materials 33, 2104878 (2021)
2D Molybdenum Carbide MXenes for Enhanced Selective Detection of Humidity in Air

[9] A. Agresti et al. Nature Materials 18, 1228-1234 (2019)
Titanium-Carbide MXenes for Work Function and Interface Engineering in Perovskite Solar Cells

[10] S.A. Sergiienko et al. International Journal of Hydrogen Energy 46, 11636-11651 (2021)
MXene-Containing Composite Electrodes for Hydrogen Evolution: Material Design Aspects and Approaches for Electrode Fabrication