Realising two-dimensional heavy fermions in rare-earth intercalated transition metal dichalcogenides

ongoing

Quantum materials exhibit unique emergent phases driven by many-body interactions, and a major goal of material science is to harness their properties. Importantly, such materials are sensitive to external stimuli by often being close to quantum criticality, where fluctuations near critical points give rise to phenomena like high-temperature superconductivity and exotic magnetic phases. This opens routes for manipulating and controlling key quantum states. Heavy fermions (HF), characterized by competing magnetic and Kondo interactions, are central to quantum criticality. Dimensionality reduction is an exciting route to control the ground states of HF, as lower dimensions enhance fluctuations and electron correlations. However, the intermetallic nature and thus three-dimensionality of conventional HF make accessing two-dimensional (2D) HF challenging. The project aims to establish intercalated transition metal dichalcogenides (I-TMDCs) as a versatile platform for realizing HF phases in 2D monolayer films. I-TMDCs are ideal for engineering Kondo physics. Their layered structure enables creation of new electronic phases via intercalation. The flexibility in choosing intercalant, host material, and intercalation ratio adds tunability over magnetic and electronic properties, while also providing a route to dimensionality reduction in 2D films. This project will leverage the precision of molecular-beam epitaxy (MBE) in combination with the advanced spectroscopic techniques angle-resolved photoemission spectroscopy (ARPES) and low temperature scanning tunnelling microscopy (STM). Together with theoretical modelling, the methods will offer a comprehensive approach to determining the low energy electronic structure and ground state of I-TMDCs. By building upon conventional I-TMDCs, the project will introduce strongly correlated properties of f-electrons and HF physics via rare-earth intercalation, ultimately establishing a novel and tuneable class of 2D HF materials.