Physics Dept Seminar

April 20, Monday

Momentum space approach to electronic structure of moiré 2D materials

Prof. Daniel Massatt

Dept of Mathematical Sciences, NJIT

(Condensed Matter Physics, Host: Tyson)

Time: 11:45 am - 12:45 pm with 11:30 am teatime

Room: ECE 202

2D materials are one to a few atom thick sheets of atoms exhibiting periodicity in plane. These materials can be stacked in many ways allowing for a large range of tuning parameters to control electronic properties. One of these parameters includes a relative twist angle in plane between the various layers. While individual layers may exhibit periodicity, the global ensemble has no periodicity, and is then called incommensurate. Further, different species of 2D materials naturally have different periodicities, and become incommensurate regardless of choice of angle.

Incommensurate 2D materials with two similar periodicities form large moiré patterns resulting in exotic quantum phases including for twisted bilayer graphene correlated insulation, unconventional superconductivity, and the fractional quantum Hall effect. To understand and predict properties of moiré materials, accurate models called ab initio models derived from first principle physics are necessary. In this talk, we will overview how momentum space techniques can be used to compute electronic observables for ab initio single-particle models with controllable accuracy.