A transition-metal chalcogenide material MX3, which is a compound of a Group Ivb or Vb transition metal element, such as Zr, Nb or Ta, and a chalcogen element, such as S, Se or Te, has a crystal structure which comprises a fundamental unit consisting of a triangle pole formed of six chalcogen atoms and a metal atom located at the center thereof, wherein chains of respective triangle poles are built up parallel to each other. This structure provides various materials exhibiting peculiar properties rarely seen in other conventional materials. Typically, such materials include TaSe3 exhibiting superconductivity with a strong anisotropy, TaS3 exhibiting a Peierls transition, and NbSe3 exhibiting a CDW (Charge Density Wave) transition. Therefore, vigorous researches are being promoted to explore the properties and develop applications thereof
Further, great interest is shown in properties of a transition-metal dichalcogenide based on its low-dimensional structure, and applications thereof.
In connection with these researches, the inventors previously succeeded in forming ring-shaped crystalline microstructures of a transition-metal dichalcogenide MX2 and a transition-metal trichalcogenide MX3.
[Prior Art Document]                Patent Publication: Japanese Patent Laid-Open Publication No. 2002-255699        
These crystalline microstructures or microcrystals can maintain a crystal structure unique to each chalcogenide in the ring-shaped microstructure thereof to exhibit original properties unique to each chalcogenide based on its low-dimensional structure. Thus, these microcrystals are expected as a material applicable to a superconducting quantum interference device (SQUID) by taking advantage of superconductivity and configuration/structure thereof. Further, this technology can realize a ring-shaped microstructure having a diameter of 0.1 to 10 μm and a line width of about 10 nm which could not be achieved by photolithography as a conventional microfabrication technique, and allows properties of each chalcogenide to be achieved in a topological macrostructure necessary for various devices. Therefore, various applied researches are being made to utilize such properties and structures for various potential purposes, such as biomagnetism measurement.
As above, researches on the peculiar properties of chalcogenides are made in various sectors. Such applications of the properties are based on the premise of verification of the properties and development of handling technologies, such as forming technologies, for achieving various configurations/structures. In particular, it is desirable that the microstructure is created during the course of physically forming the crystal, and formed as a topological structure maintaining its original properties in a self-aligning manner, as in the ring-shaped microcrystal previously proposed by the inventors. This process allows an obtained microcrystal to maintain original properties unique to each chalcogenide.
The transition-metal chalcogenide material, such as transition-metal trichalcogenide or transition-metal dichalcogenide, is characterized by having low dimensionality, and thereby exhibits significant anisotropy in various properties thereof. Thus, what is required for utilizing these characteristics is to research the properties and develop a forming technique capable of coping with such anisotropy, specifically a topological shaping/forming method capable of maintaining topological properties of each transition-metal chalcogenide material in a macro configuration/structure necessary in actual use.
It is therefore an object of the present invention to provide a method capable of forming a transition-metal chalcogenide material having a topological micro configuration/structure while maintaining the crystal structure of a transition-metal trichalcogenide or dichalcogenide exhibiting the aforementioned peculiar properties to preserve the properties, and to provide a useful transition-metal chalcogenide crystal with a topological configuration/structure, having the original properties of the transition-metal trichalcogenide or dichalcogenide.
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