Embedded Files
We explore quantum condensed matter systems in solid-state devices where topological effects and quantum many-body phenomena are dominant. We are currently focusing on the experimental investigations of the following subjects
Unconventional superconductivity in quantum-engineered systems:
Superconductivity is one of the most dramatic condensed matter phenomena where quantum interactions between particles play the critical roles at very low temperature. We study such exotic quantum phenomena, esp. topological superconductivity, by fabricating artificial nanoscale devices with a goal of better understanding and controlling of the quantum interaction effects.
Topological quantum phases in 2D materials:
An application of high magnetic fields is another way to enhance the effects of the quantum interactions, and this led to the famous discovery of the emergent quantum topological phase called fractional quantum Hall effect (Nobel prize in 1997). We focus to investigate such systems where the wave function topology and quantum interactions are both important, leading to the new topological quantum phases. We also pursue the realization of exotic topological quasiparticles in these systems that could lead to the applications such as fault-tolerant topological qubits.
Development of quantum sensor microscopes (i.e. quantum sensors + customized AFM):
Signals emanating from the samples of delicate quantum phases are often very subtle to detect, especially in extreme conditions such as nano-sized samples in cryogenic temperatures. We place our efforts on the development of sensing techniques which utilize quantum mechanical effects to enhance the sensitivity of measurements for various physical quantities, and obtain spatially-resolved images by utilizing cryogenic nano-positioning systems. The nanoscale quantum sensors we use are SETs, SQUIDs, HEMTs, SAGNAC interferometers and mechanical-resonator force sensors.
Fabrication of high-quality Josephson junctions to access superconducting phase information and to study superconducting qubits for quantum information.
We nanofabricate various superconducting Josephson junctions to use as a quantum computing element with a long coherence time of quantum information, and also to investigate superconducting order-parameters of various exotic materials. We actively use the technique of e-beam lithography and the cryogenic microwave engineering to access the true quantum nature of macroscopic solid-state devices.
We also frequently employ nano-fabrication techniques and cryogenic measurements as means to control 'quantum many-body effects' in condensed matter systems. The followings are the main setups in our lab.
Dedicated measurement systems
Bluefors Dilution refrigerator (8 mK, 9T-3T vector, active vibration cancellation frame, fast-sample-exchange option)
Oxford instruments Teslatron (1.5K, 14T)
Montana instruments optical cryostat (~3K)
Sungwoo inst. cryostat (4K, 1T)
2D materials fabrication setup with an Olympus BM-51 microscope in a glovebox
Modifed AFMs and other scanning probes
Low temperature Magnetic Force Microscopy & Kelvin Probe Force Microscopy module
SAGNAC and other fiber-based laser interferometers
High speed (DC~GHz) electrical measurement setups
Dilution refrigerator with a 9T-3T vector magnet and a fast sample exchange option installed in an active vibration cancellation frame.
Others in shared facilities at SNU
Others in shared facilities at SNU
Photo and e-beam lithography
Deposition systems (thermal, e-beam, sputtering etc.)
SEM (Scanning Electron Microscope), FIB (Focused Ion Beam)
Page updated
Google Sites
Report abuse