Intercalating\nArchitecture for the Design of Charge\nDensity Wave in Metallic MA<sub>2</sub>Z<sub>4</sub> Materials

We present a novel approach to induce charge density\nwaves (CDWs)\nin metallic MA<sub>2</sub>Z<sub>4</sub> materials, resembling the\nbehavior observed in transition metal dichalcogenides (TMDCs). This\nmethod leverages the intercalating architecture to maintain the same\ncrystal field and Fermi surface topologies. Our investigation reveals\nthat CDW instability in these materials arises from electron–phonon\ncoupling (EPC) between the <i>d</i> band and longitudinal\nacoustic (LA) phonons, mirroring TMDC’s behavior. By combining\nα-MA<sub>2</sub>Z<sub>4</sub> with 1<i>H</i>-MX<sub>2</sub> materials in a predictive CDW phase diagram using critical\nEPC constants, we demonstrate the feasibility of extending CDW across\nmaterial families with comparable crystal fields and reveal the crucial\nrole in CDW instability of the competition between ionic charge transfer\nand electron correlation. We further uncover a strain-induced Mott\ntransition in β<sub>2</sub>-NbGe<sub>2</sub>N<sub>4</sub> monolayer\nfeaturing star-of-David patterns. This work highlights the potential\nof intercalating architecture to engineer CDW materials, expanding\nour understanding of CDW instability and correlation physics.