Ferroelectricity and superconductivity in bilayer MoTe₂ under hydrostatic pressure

In van der Waals (vdW) layered materials, tuning of the stacking order can have significant influence on the electronic band structure and transport properties, with quantum phenomena being forbidden or allowed as determined by the crystal symmetry. For bulk T_d-phased MoTe₂, calculations and experiments suggest that pressure can significantly tune the layer seperation and interlayer coupling, thus modifying superconductivity [1]. In bilayer MoTe₂, the noncentrosymmetric T_d-structure further allows an unconventional interlayer sliding ferroelectricity which could coexist with superconductivity and could be driven by electrical gating [2]. In this presentation, we will demonstrate our exploration of the pressure effects on superconducitivity and ferroelectricity in bilayer MoTe₂. We investigate the evolution of ferroelectric switching and superconductivity under pressure up to 2 GPa with control over carrier doping, displacement field, magnetic field, and temperature. To reduce strain and improve device quality, we fabricate the Hall device compeletly with two-dimensional materials. Our work provides a complete phase diagram of coupled superconductivity and ferroelectricity in bilayer MoTe₂ as a function of electrical gating and pressure.

[1] Heikes, Colin, et al. Mechanical control of crystal symmetry and superconductivity in Weyl semimetal MoTe₂. Physical Review Materials 2.7 (2018): 074202.

[2] Jindal, Apoorv, et al. Coupled ferroelectricity and superconductivity in bilayer T_d-MoTe₂. Nature 613.7942 (2023): 48-52.