A

Amorphous alloy
Common metals and alloys have a crystal structure in which the atoms are arranged periodically. At the same time, these metals and alloys take liquid form under high temperatures, and the atomic arrangement takes on a random structure. When cooled rapidly from this high-temperature liquid state, it does not crystallize, but maintain its random structure and solidifies to form a solid. These alloys are called “amorphous alloys.” They are also differentiated by the term “metallic glass,” which is clearly observed in the glass transition phenomenon when the temperature rises during a specific heat experiment.
Amorphous phase
This refers to the random phase of the atomic arrangement, unlike the crystalline phase wherein the atomic arrangement is periodic (repetitive).
Amperometry
This is an electrochemical method for measuring the current flowing through when a constant electrical potential is applied to electrodes. Electrical currents arise through the oxidation/reduction of molecules on the electrodes. The size of the currents and the concentration of the redox molecules are proportional, thereby making possible their use in quantitative analysis.
Angle-resolved photoemission spectroscopy
Electrons are emitted from the surface of matter when ultraviolet rays or X-rays are irradiated on the crystals. The electrons emitted are called photoelectrons. When the energy and momentum (angle) of these photoelectrons are measured, we can determine information about the state of the electrons in the matter in which the electrons were originally found; in short, we can find out the electronic state of the matter.
Atomic-force microscopy
Using an extremely sharp needle (probe) called a cantilever, the force acting between the atoms of the sample and the probe is detected, and the shape of the surface of the sample is obtained.

B

Band gap
This refers to the energy gap between the highest energy level occupied by electrons and the lowest energy level not occupied by electrons in a semiconductor. The band gap is an important parameter when using semiconductors as electronic devices.
Barrier in reaction
This refers to the level of energy that must be exceeded for a chemical reaction to occur.
Biosensor
This is a chemical sensor that uses matter of biological origin as a molecular recognition element. For example, there are sensors that utilize the specific bonding of antigens and antibodies, and DNA sensors that utilize the bonding of DNA that are complementary to one another.
Biotemplating
A method for arranging and synthesizing inorganic materials using biological supramolecules.

C

Carbon nanotube
Carbon nanotube is a material that comprises of carbon atoms lined up in the form of a tube, with the diameter ranging from several nanometers (one nanometer=one billionth of a meter) to several tens of nanometers. It was discovered by Professor Sumio Iijima (from Tohoku University) in 1991.
Charge density wave
This refers to the phenomenon wherein electric charges carried by electrons have different periodic cycles from the periodic cycles of crystals, and are distributed regularly. It is known to have played an important role in the discovery of various specific physical properties of semiconductors and metals, such as superconductivity, and is a phenomenon that is frequently observed in matter that has particularly low dimensionality.
Chip device
A chip device contains sensors, etc. placed on top of a substrate such as glass or plastic that is a few centimeters square in size.
Cocatalyst
This refers to matter that attains improvements in performance through the addition of a small amount of cocatalyst. The cocatalyst plays various roles, including functioning as an active site, promoting multi-electron reaction through the accumulation of electric charge, and promoting charge separation.
Comb-type electrode
This is one of the array electrodes that is created using micromachining technology. Electrodes with an extremely narrow bandwidth are placed close to one another, making it possible to efficiently induce a redox cycle.
Complex hydrides
This refers to high-density hydrogen compounds that have been stabilized through ionic bonding between metal ions that have positive charge, such as lithium ions and sodium ions, and hydride ions that have negative charge, such as boron hydride ions (BH4-).

D

De-alloying method
This method involves selectively corroding and eluting specific elements from alloy. It is also known as selective corrosion.
Dirac electron
Electrons responsible for conducting electricity within a solid normally move with a finite effective mass. However, Dirac (1933 Nobel Prize in Physics), a British physicist, predicted theoretically about 80 years ago that under extraordinary circumstances, these electrons will move within a solid in accordance with the “Dirac equation” that he had proposed. This equation describes the movement of relativistic fermions with zero mass. Electrons in this state move very easily, and hence are characterized by the ease with which they exhibit a quantum effect.
Dislocation
This refers to the situation in which a disturbance arises along one line of an atomic arrangement or crystal lattice as a result of factors such as external pressure.
Doping
Doping refers to the act of intentionally adding a small amount of an impurity element that is not present in the host crystal. This is an important technology for controlling the structure and physical properties of crystals.