Theme 3 colloquium by prof. Jianting Ye (RUG): 'Field Effect Control of Quantum Phases in 2D Materials' (Lecture)

Many recent discoveries on novel electronic states were made on 2D materials. Especially by making artificial bilayer systems, new electronic states such as unconventional superconductivity and orbital ferromagnetism have been reported. This talk will discuss quantum phase transitions and Ising superconductivity induced in 2D transition metal dichalcogenides. Using ionic gating, quantum phases such as superconductivity can be induced electrostatically on many 2D materials. Ionic gating can access electronic states with broken local inversion symmetry while maintaining global symmetry. Field effect control of the Josephson and spin-orbit coupling is essential for realizing many exotic electronics states predicted for the coupled bilayer superconducting systems with strong spin-orbit interaction.

In transition metal dichalcogenides, Ising-like paring states can form, showing a robust orthogonal spin-protection and record-high upper critical field. We will discuss 1) how to improve the mobility of induced carriers and enter the clean regime of Ising superconductivity. And 2) how to couple two Ising superconducting states through Josephson coupling to form FFLO states, control the strength of Ising paring, and access electronic states with broken local inversion symmetry while maintaining the global inversion symmetry. Ionic gating Field-effect control of the Josephson and spin-orbit coupling is essential for realizing many exotic electronics states predicted for the coupled bilayer superconducting systems with strong spin-orbit interaction.