Research

The research goals of PIRE:HYBRID are:

RG1: Discover new hybrid materials, and search for emergent phenomena that can only be realized at hybrid interface

RG2: Disseminate scientific outcomes of PIRE:Hybrid within the expert and broader communities.

RG3: Prepare hybrid materials and devices for technology transfer to industry.

Materials thrust (Leader: Hocevar; Palmstrøm, Petek, Plissard, Hunt)

The objective of this thrust is to synthesize novel hybrid interfaces and unravel their chemical and structural properties. Fabrication of 2D and 1D superconductor/semiconductor interfaces will be combined with in-situ and ex-situ characterization of interface formation and of their structural and chemical properties. A perfect interface is abrupt and is free of misfit dislocations, grain boundaries, cross-contamination and interfacial phases. This is challenging for metal/semiconductor interfaces for two main reasons: (1) the high diffusivity of metal atoms which leads to fast 3D nucleation and the formation of grains, (2) the high reactivity of metals with the semiconductor interface.

Devices thrust (Leader: Hatridge; Frolov, Hunt, De Franceschi)

This thrust’s goal is to realize superior quantum devices incorporating hybrid materials.  We will demonstrate superconducting, hybrid and topological qubits as well as produce basic devices to characterize new materials as they are produced.  Hunt and Hatridge will focus on layered van der Waals hybrid junctions for superconducting qubits, Frolov and De Franceschi on nanowire and planar superconductor/semiconductor hybrid structures for topological qubits.  Investigators will perform magneto-transport characterization (Frolov, Hunt, De Franceschi) and microwave response characterization (Hatridge). The results will be used as feedback for the other thrusts; as new materials are mastered they will be incorporated to improve quantum bit performance.

Theory thrust (Leader: Marom; Pekker, Houzet, Meyer, Waintal)

Theory will be used in both interpretive and predictive capacities, to explain experimental observations and to guide synthesis, characterization, and fabrication. The goal of the theory thrust is to predict the properties of realistic quantum nano-devices. This requires a multiscale approach bridging between atomistic interface properties obtained from ab initio calculations to mesoscopic device transport properties (like current-voltage characteristics), measured in experiments.

The theory team brings together a combination of expertise on all the relevant length scales and complementary analytical and computational skills. Marom is an expert on first principles simulations, including density functional theory (DFT) and many-body perturbation theory. She is the developer of the massively parallel genetic algorithm (GA) package, GAtor. Waintal is an expert on tight binding and quantum transport. He is the developer of an open source quantum transport code, KWANT, whose time dependent extension, t-KWANT, currently holds the world record for system size and simulation time scale. Houzet and Meyer are experts on the theory of mesoscopic superconductivity. They are leaders in the field of topological superconductivity and Majorana fermions. Pekker is an expert on dynamics of interacting many-body quantum systems, including transport in mesoscopic and nano-devices.