Device Fabrication and Characterization Group for Quantum Metrology

In order to explore and understand electronic, magnetic and photonic properties of new novel materials, in particular superconducting thin films, nanowires and nanolayers of layered materials or topological insulators, we fabricate nanostructures/nanodevices by using state of the art lithography tools such as focused ion beam microscope and e-beam lithography. Successful creation of these nanodevices gives access to many novel experiments and we investigate them at the nanoscale level.

Magnetic and/or superconducting based tailored structures have many promising device functionalities, which besides high science form the basis of memory, photo detection and magnetic sensing devices. Using a MPMS system investigates the low temperature electrical, magnetic and photo-conducting response of nanostructures/ meanders/ proximity junctions - based on magnetic and/or superconducting materials.

Using Dilution Refrigerator in mK region characterize: transport properties of nanowires and 2DEG systems for possible observation of Quantum Phase Slip(QPS); transport properties of junctions comprising superconductor with different materials such as insulator, normal metal and ferromagnets for observations of Andreev Reflection and noise analysis; and studies on conductance quantisation, Quantum Hall Effect and fractional Quantum Hall Effect in 1D and 2DEG systems for the realisation of Quantum resistance standards.

Operation and maintenance of Quantum Voltage standard (Programmable Josephson Voltage Standard system) which is the primary standard for voltage up to 10 ‘Volt' level. The system is being used for dissemination of unit ‘Volt' in India through calibration of national standards to maintain the traceability chain at 1.018 V and 10 V. The activity also involves the low temperature and microwave measurement on superconducting thin films and devices.

Under the XII-Five Year project activity entitled “Advanced Quantum Research and Innovation with Ultra Small Systems(AQuaRIUS)”  And  Policy and Road Map Document of CSIR-NPL, R&D on Superconducting Nanowire Single Photon Detectors (SNSPDs) is in progress.Specific tasks projected in the initiative of establishing superconducting nanowire single photon detection (SNSPD) system  are related to develop a facility for single photon detection, which will be the first one in the country and among very few in the whole world. Once the high accuracy SNSPD is developed this would serve as national facility for characterization of single photon source and for single photon detection. This facility would be used further to perform basic and challenging experiments in quantum optics, and to perform applied research in quantum computing, communication, imaging, and cryptography.