Condensed Matter Experiment Ⅰ

Low Temperature Materials Science

Staff

Associate Professor : Tsutomu Nojima
Assistant Professor : Shintaro Nakamura

Research

Schematic drawing of the electric double layer transistor (EDLT) configuration.

Superconductor – insulator transition observed in a high-Tc superconductor film, which is caused by electrostatic carrier doping using an EDLT configuration.

The handmade magnetometer employing Faraday balance and 3He cryostat for the measurements of DC magnetization at low temperatures down to 300 mK.

Our group studies the quantum phenomena occurring at low temperatures in various superconductors and highly-correlated electron systems. In addition to understanding the fundamental properties of these materials, we focus on controlling them in the form of thin films and devices, which leads to finding novel physical phenomena. The current research subjects are the electric-field-induced superconductivity, two dimensional superconductivity with atomic-layer structures, exotic superconductivity in magnetic fields, and the ground state of rare earth compounds, as described below

1) Electric field induced superconductivity:
By using electric double layer transistor (EDLT) configurations, we induce the conduction carries electrostatically in the thin films or on the surfaces of insulators and explore the novel superconducting phenomena and mechanisms by tuning the carriers. Especially, we are interested in the superconductivity with broken inversion symmetry and the ambipolar doping effect in cuprates.

2) Vortex matter physics:
Recently emerging high-Tc superconductors such as cuprates, MgB2 and iron pnictides (chalcogenides) show peculiar features in their mixed states (vortex states) due to the strong thermal fluctuation and/or multi-band effect. We are studying them by using magnetization, magnetic torque and transport measurements.

3) Ground state and quantum phase transition in highly correlated electron systems:
Magnetic phase transitions and non-Fermi liquid states around absolute zero are studied in Ce based compounds by thermodynamic and transport measurements.

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