arXiv subjects

Maciej Śmiertka

Publications and source records attributed to Maciej Śmiertka.

2 recordsLinked to original sources

arXiv2026

Coherent interaction of WS$_2$ and quasi-2D perovskite excitons over micrometer distances via a cavity field

The coherent coupling of cavity-confined photons and excitonic matter resonances leads to the formation of cavity polaritons, hybrid light-matter quasi-particles. If multiple exciton resonances couple to the same photonic mode, the resulting polariton constitutes a coherent interaction between matter resonances that can be spatially separated without any direct electronic coupling. In this work, we demonstrate the formation of such a coherent coupling at room temperature using an open optical cavity containing two distinct van der Waals materials - monolayer WS2 and layered quasi-2D halide perovskites (HaPs) - separated by $1.5 μ\rm m$. The system forms three polariton branches, with the middle branch possessing nearly equal fractions of both excitons and the photonic mode. White-light reflectivity and luminescence measurements are in good agreement with simulations using a coupled harmonic oscillator and a microscopic Wannier-Hopfield framework. Our results lay the foundation to combine highly complementary degrees of freedom in 2D materials in an in-situ tunable fashion to enable new polaritonic functionalities.

cond-mat.mes-hall↗

arXiv2026

Geometry-Controlled Magnetic and Electronic Landscapes in Anisotropic van der Waals Materials

Electronic structure in van der Waals materials is commonly engineered through composition, strain, electrostatic gating and heterostructure assembly. Here we introduce geometronics, a concept in which substrate geometry locally reorients an anisotropic crystal, transforming homogeneous external perturbation into programmable magnetic and electronic landscapes. We demonstrate this concept using a bilayer of the antiferromagnetic semiconductor CrSBr transferred onto an inverted pyramidal nanoindentation, where the local crystal orientation with respect to the external magnetic field drives the coexistence of antiferromagnetic and ferromagnetic phases within a single continuous crystal. The resulting magnetic landscape creates a switchable excitonic potential well of up to 10--12 meV, directly visualised by spatially resolved spectroscopy. More generally, geometronics provides a universal route for deterministically programmed electronic and magnetic landscapes without modifying the material itself. It therefore establishes substrate topography as a new design principle that exploits the intrinsic anisotropy of layered van der Waals materials.

cond-mat.mtrl-sci↗