Research

NP Lab at Caltech investigates fundamental quantum electronic phenomena in novel materials and nanoscale devices with potential applications in quantum nanoscience. Our main focus is on devices based on two-dimensional materials only a few atoms thick — promising platforms for studying topological and correlated electronic quantum states. For further information, contact Stevan or explore our publications.

Van der Waals Heterostructures

Van der Waals heterostructure schematic

Two-dimensional materials offer unlimited possibilities for designing novel structures to explore electronic correlations and topological phenomena. By stacking atomically thin layers — graphene, hexagonal boron nitride, transition metal dichalcogenides — we create van der Waals heterostructures with precisely controlled properties. Besides their importance in fundamental condensed matter physics, these structures have great potential for future quantum science applications.

Superconductivity in strongly correlated graphene structures

When two-dimensional layers are stacked at a slight twist angle, the resulting moiré superlattice can dramatically reshape the electronic band structure. In magic-angle twisted bilayer and multilayer graphene, flat bands give rise to a rich phase diagram including unconventional superconductivity, correlated insulating states, and orbital magnetism. Our group has demonstrated enhanced superconductivity through spin-orbit proximity effects and twist-angle engineering, and has mapped the hierarchy of symmetry-broken phases using both transport and STM.

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Scanning Tunneling Microscopy

Our lab operates millikelvin scanning tunneling microscopes capable of atomic-resolution imaging and spectroscopy at extremely low temperatures. This enables direct visualization of electronic order parameters — charge density waves, pair density modulations, inter-valley coherent order, and nematic states — in two-dimensional quantum materials.

Key publications:

Topological Quantum Matter

Our group has a long-standing interest in topological phases of matter, from topological insulators and crystalline insulators to Majorana fermions in hybrid superconductor-semiconductor systems. Our earlier work on atomic chains on superconductors provided landmark evidence for Majorana modes, and we continue to explore topological phenomena in moiré and van der Waals platforms.

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