Researcher

Research Activities

Recent advancement in engineering technologies allow us to create new alloys by designing atomic positions and their device implementation in nanometric scale (about 1/100,000 of the diameter of a hair). In such a very small scale, quantum mechanics dominates the physical behaviours of electrons and spins, which are different from what we experience in our daily life as governed by the classical mechanics and electromagnetism. By combining these behaviours and the corresponding principles, we have been developing new magnetic materials and their devices to contribute to the sustainable society.

Quantum Nanoelectronics (Prof. Hirohata)

• Development of a new magnetic material
• Development of a new quantum nanoelectronic device
• Characterisation of a nanoelectronic device

1. Development of a new magnetic material
   In the conventional electronics, information can be carried and stored by an electron charge. By utilising another feature of an electron, i.e., up and down electron spins, the information density can be increased and their quantised states can be used in quantum computation. A major obstacle here is the difficulties to fabricate a magnetic material to produce only one of the spins in a nanometric size for device implementation. In our group, we have been investigating a ternary/quaternary alloy, as known as a Heusler alloy, through prediction by machine learning and demonstration by ultrahigh vacuum growth techniques.
2. Development of a new quantum nanoelectronic device
   In the quantum world, many unique phenomena can be observed, e.g., the leakage of an electron spin in a confined device as well as the superposition and interference of spins. We have been designing a new quantum nanoelectronic devices to achieve these phenomena at high efficiency by implementing the abovementioned new materials. We have also been developing and evaluating a new fabrication process by combing atomically controlled growth and patterning.
3. Characterisation of a nanoelectronic device
   It has been a common practice to charaterise a material and device in nanometric resolution using transmission electron microscopy by thinning them below 100 nm in thickness. Such thinning, however, introduces defects and strain in a sample, which may hinder the intrinsic properties. Accordingly we have established a non-destructive imaging method by controlling an acceleration voltage of an electron beam in scanning electron microscopy. Our method can be applied for in situ observation under device operation.