arXiv subjects

Justine Cordiez

Publications and source records attributed to Justine Cordiez.

4 recordsLinked to original sources

arXiv2026

Doping-controlled topological superconducting transition in misfit layer compounds

Achieving topological superconductivity is a key goal in quantum physics, offering a path to fault-tolerant quantum computers. A central challenge in this field is to continuously drive a material through a topological quantum phase transition to directly observe the evolution from trivial to topological superconductivity. However, finding a robust platform that allows such extreme and precise tuning remains a challenge. Here, we demonstrate a doping-controlled phase transition from a conventional to a topological superconducting state in the bulk misfit layer compound (LaxPb1-xSe)1.14(NbSe2)2. We reveal a non-monotonic phase diagram characterized by two distinct superconducting regimes separated by a non-superconducting phase at a precise doping. In the highly doped regime, the superconducting phase becomes remarkably sensitive to non-magnetic disorder, and orientation-selective in-gap modes emerge at atomic step edges. Supported by Bogoliubov-de Gennes calculations, these emergent spatial signatures are consistent with a time-reversal-symmetric crystalline-topological order parameter. Our results establish misfit compounds as a platform to engineering topological superconductivity.

cond-mat.supr-con↗

arXiv2026

Doping tunable charge density waves in misfit layer compounds

The ability to tune charge density waves (CDWs) through external control knobs, such as doping, pressure or strain is crucial for exploring the phase diagram of two dimensional (2D) or quasi-2D materials. Yet, controlling CDWs critical temperature and ordering vector remains a challenge for current experimental techniques. In this work, we establish misfit layer compound heterostructures as a reliable platform to manipulate CDWs in transition metal dichalcogenides. By combining ab initio calculations with low-temperature scanning tunneling microscopy, we show how to achieve doping tunable control over NbSe2 CDW by chemically alloying in the rocksalt subunit. Crucially, we prove that tuning the La Pb ratio in the misfit family (LaxPb1xSe)1.14(NbSe2)2 enables stabilization of different CDW orders, such as 2x2 or 3x3 patterns, and even coexisting phases. This work paves the way for engineering transition metal dichalcogenides with tailored charge density waves within misfit heterostructures.

cond-mat.mtrl-sci↗

arXiv2026

Tuning the Charge Transfer of Transition Metal Dichalcogenides via Misfit Layer Compounds

Misfit layer compounds (MLCs) are a versatile platform for exploring the electronic phase diagram of two dimensional (2D) materials beyond the limits of conventional gating techniques. This work demonstrates the precise tunability of electron doping in NbSe2 monolayers through chemical alloying within the rocksalt layer of (LaxPb1xSe)1.14(NbSe2)2 heterostructures. By combining first principles density functional theory (DFT) calculations with angle resolved photoemission spectroscopy (ARPES), we prove that the rocksalt unit acts as an universal electron donor. We show that varying the La Pb ratio results in a rigid Fermi level shift, still preserving the NbSe2 electronic structure. Crucially, photon energy dependent ARPES confirms that the NbSe2 layers nearly maintain their intrinsic 2D character and orbital identity within the three dimensional misfit. This study establishes MLCs as a reliable platform for engineering emergent states in 2D transition metal dichalcogenides through precise stoichiometric control.

cond-mat.mtrl-sci↗

arXiv2024

NbSe$_{2}$'s charge density wave collapse in the (LaSe)$_{1.14}$(NbSe$_{2}$)$_{2}$ misfit layer compound

Misfit layer compounds, heterostructures composed by a regular alternating stacking of rocksalt monochalcogenides bilayers and few-layer transition metal dichalchogenides, are an emergent platform to investigate highly doped transition metal dichalcogenides. Among them, (LaSe)$_{1.14}$(NbSe$_2$)$_2$ displays Ising superconductivity, while the presence of a charge density wave (CDW) in the material is still under debate. Here, by using polarized Raman spectroscopy and first-principles calculations, we show that NbSe$_2$ undergoes a doping-driven collapse of the CDW ordering within the misfit, and no signature of the CDW is detected down to 8~K. We provide a complete experimental and theoretical description of the lattice dynamics of this misfit compound. We show that the vibrational properties are obtained from those of the two subunits, namely the LaSe unit and the NbSe$_2$ bilayer, in the presence of a suitable field-effect doping, and then highlight the 2D nature of the lattice dynamics of NbSe$_2$ within the (LaSe)$_{1.14}$(NbSe$_2$)$_2$ 3D structure.

cond-mat.mtrl-sci↗