Overview of Materials Science Research

Overview of Materials Science Research

Hideaki Takayanagi
Materials Science Laboratory
　The Materials Science Laboratory (MSL) aims at producing new materials to discover quantum phenomena for new functions. The materials including those that do not exist in nature are produced by controlling the configuration and coupling of atoms and molecules. To accomplish these goals from different perspectives the following four MSL groups are formed. They cover research fields of various materials ranging from inorganic matter, such as semiconductors, to organic matter, such as neurotransmitters. The characteristic feature of MSL is the effective sharing of the unique nanofabrication and measurement techniques of each group. This enables fusion of research fields and techniques, which leads to innovative material research for the IT Society.

Molecular and Bio-Science Research Group
Create new organic materials by manipulating single molecules, and investigate information processing devices based on neural functions.

Superconducting Thin Films Research Group
Study high-Tc superconductors by fabricating top quality samples through the molecular beam epitaxy(MBE) method and develop its applications to microwave communication.

Superconducting Quantum Physics Research Group
Investigate theoretical and experimental research on a quantum computers superconductors and new magnetic devices using quantum dot arrays.

Spintronics Research Group
Aim to control the spin degrees of freedom in semiconductors to achieve new device functions for the next generation electronics.
　

　 The following are four major results obtained in the fiscal year 2002.

1. The response of the neural circuit grown from rat brain neuron is measured by means of unique microelectrode arrays with newly developed stimulation technique that guarantees excellent reproducibility. The obvious correlation between stimulus pattern and the response infers that the brain memory is based on neural level mechanism.

2. First growth of Nd₂CuO₄-type structured La₂CuO₄ succeeded, which has been known as K₂NiF₄-type only since low temperature growth is difficult without our MBE technique. The growth parameters to choose each structure are fully investigated.

3. Plaquette super lattice formed by InAs quantum wires embedded in InGaAs substrates is predicted to be a superconductor at the transition temperature 2 times higher than that of simple square lattice. The difference is large enough to be observed experimentally. This shows that material property can be designed by controlling dot structural parameters.

4. Modification of Rashba spin-orbit interaction strength in InGaAs quantum wells is observed as a function of structural asymmetry. The interaction coefficients first systematically obtained by measuring magnetic resistance show good agreement to the theoretical values.

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	The following are four major results obtained in the fiscal year 2002.
1.	The response of the neural circuit grown from rat brain neuron is measured by means of unique microelectrode arrays with newly developed stimulation technique that guarantees excellent reproducibility. The obvious correlation between stimulus pattern and the response infers that the brain memory is based on neural level mechanism.
2.	First growth of Nd₂CuO₄-type structured La₂CuO₄ succeeded, which has been known as K₂NiF₄-type only since low temperature growth is difficult without our MBE technique. The growth parameters to choose each structure are fully investigated.
3.	Plaquette super lattice formed by InAs quantum wires embedded in InGaAs substrates is predicted to be a superconductor at the transition temperature 2 times higher than that of simple square lattice. The difference is large enough to be observed experimentally. This shows that material property can be designed by controlling dot structural parameters.
4.	Modification of Rashba spin-orbit interaction strength in InGaAs quantum wells is observed as a function of structural asymmetry. The interaction coefficients first systematically obtained by measuring magnetic resistance show good agreement to the theoretical values.