Research Projects

Harnessing emergent quantum phenomena in materials has the potential to transform energy and information technology. Layered van der Waals (vdW) materials, with their unprecedented ability to control electronic properties via two-dimensional (2D) material stacking, are emerging as versatile tools in condensed matter physics. Among these, transition metal dichalcogenides (TMDCs) offer unique tunability, as they accommodate atomic intercalation and can host competing electronic orders. Traditionally, vdW heterostructures are assembled by stacking monolayers at varied twist angles and symmetry-breaking configurations, enabling correlated electronic phases. However, achieving such control in bulk TMDCs has remained challenging. Self-stacked heterostructures (4Hb and 6R phases) present an untapped opportunity to explore complex, correlated electronic phases. In these structures, the weak interlayer interactions allow each layer to retain its intrinsic properties, making the properties of vdW heterostructures highly customizable based on layer composition and stacking sequence. By adjusting interlayer coupling, these materials can unlock exotic quantum behaviors. An exciting, largely unexplored frontier is the stacking of strongly correlated quantum phases. This project will focus on synthesizing 4Hb and 6R phases tantalum based mixed dichalcogenides, such as TaSSe, TaSTe, and TaSeTe. These materials, with alternating 1H (TaX2) and 1T (TaY2) monolayers (X, Y=S, Se, Te), exhibit charge density waves (CDW) and a correlated insulating phase. Interlayer coupling and proximity effects are anticipated to influence correlation-driven orbital textures, making them promising systems for investigating correlation physics in two dimensions. Additionally, the non-centrosymmetric nature of 1H layers, along with significant spin-orbit coupling, suggests the possibility of strong spin-valley locking in 1H-derived bands. The primary goal is to unravel the hidden electronic structure and collective ground states of these layered systems by conducting comprehensive angle-resolved photoemission spectroscopy (ARPES) and confirming any presence of charge modulations with their propagation vectors though synchrotron-based diffuse scattering (DS) experiments. Additionally, the microscopic origins of CDWs will be identified through experimental measurements of phonon dispersion and linewidth. The project will begin with establishing a single-crystal growth facility via the chemical vapor transport (CVT) method for producing bulk heterostructures, followed by comprehensive characterization of their transport, magneto-transport, and magnetic properties. This approach will deepen our understanding of structure-property relationships and assess these materials' potential for future device applications.