Kiguchi/Nishino Laboratory

Laboratory Introduction

Professor Kiguchi

Associate professor Nishino

Assistant professor Kaneko

Assistant professor Fujii

Laboratory name Kiguchi/Nishino Laboratory
Staff Professor Manabu Kiguchi
(The 1st floor of West Bldg.4, room 102B/E-MAIL:kiguti@chem.)
Associate professor Tomoaki Nishino
(The 1st floor of West Bldg.4, room 107/E-MAIL:tnishino@chem.)
Assistant professor Satoshi Kaneko
(The 1st floor of West Bldg.4, room 107/E-MAIL:skaneko@chem.)
Assistant professor Shintaro Fujii
(The 1st floor of West Bldg.4, room 107/E-MAIL:fujiis@chem.)

*Please put titech.ac.jp on the E-MAIL.

Research Content

 

We are interested in investigating electronic phenomena appearing in a variety of materials extended from single molecules to molecular assemblies (nano to macro), and comprehensively understanding the physical chemistry basis behind. Our research activities span development of new class of materials, clarifications of their electronic, electron transport and magnetic properties, and discoveries of new phenomena specific to nano-systems.


New classes of carbon nanostructures and their unconventional electronic and magnetic propertie

We have a large variety of carbon allotropes having different electronic properties, as we know from the fact that diamond is an insulator with extreme mechanical hardness, whereas graphite is an electrical conductor with layered structure which can be easily cleaved. This variety originates from the variety of C-C bonding manners, such as single, double and triple bondings. Fullerenes such as C60, carbon nanotubes, and graphene (single sheet of graphite) are also involved in the carbon allotropes. We have been challenging to create nanosized graphene (nanographene) and to clarify its electronic and magnetic properties. The electron in a nanographene sheet has behavior entirely different from that in conventional conducting materials, as a consequence of quantum effect and geometrical effect on the electrons confined in the nanosized two dimensional sheet. From chemistry aspect, the electronic structure of nanographene can be understand along the line of structural organic chemistry, as it is what is extrapolated from condensed polycyclic hydrocarbon molecules such as naphthalene, anthracene to nanodimension. The development of the interdisciplinary frontier between condensed matter physics and structural organic chemistry is our challenge in the research on nanographene.

We are interested also in carbon nanomaterials with their structures intermediate between diamond and graphite, and nanographene-based nanoporous materials. Guest species confined into the nanospace not only have structures entirely different from those in the bulk state, but also show unconventional electronic and magnetic properties.



Schematic model of nanographene (left), Alkali metal clusters regularly arranged in a nanopore space of carbon nanomaterial (right).



Single molecular junction

When a single molecule is bridged between metal electrodes, the single molecule could show interesting phenomena which can not be observed in its bulk phase. The single molecular junction has also attracted wide attention due to its potential application for future electronic devices. We have been challenging to fabricate well defined single molecular junctions and to investigate their electrical conductivity in various condition (in air, solution, ultra high vacuum) using STM and mechanically controllable break junction. We are also challenging to develop the vibration spectroscopy of a single molecular junction to see the single molecule bridging between metal electrode. We have revealed that the highly conductive single molecular junctions could be prepared by direct binding of the π-conjugated organic molecule, such as benzene and C60, to the metal electrodes without the use of anchoring groups.


Schematic model of single molecular junction (left), Vibration spectroscopy of a single benzene molecule bridging between Pt electrodes (right)



Microprobe observations and investigations of nanostructures in the atomic resolution

Scanning Probe Microprobe (SPM) techniques, which are based on electron tunneling phenomenon and forces created by chemical interactions, can offer direct information of atomic arrangements and electronic structure of nanostructures in the atomic resolution. We have been investigating the geometrical atomic arrangements and the local electronic structures of nanographene, graphene edges, and nanostructures created by the reaction of nanographene with chemical species such as oxygen, by means of scanning tunneling microscopy/spectroscopy and atomic force microscopy. Microprobe investigations at low temperature and under strong magnetic field give information on the detailed structures and can unveil unconventional behavior of the electrons confined into the nanospace.



Low temperature scanning tunneling microscope with a high field magnet (left). Electron confinement in a finite size graphene zigzag edge observed by scanning tunneling microscope (right).



New functional materials in molecule-based architecture

Organic molecules are electrically insulating and magnetically inactive as a consequence of the formation of electron pairs in general. Recent development of molecular designing and sophisticated synthesis techniques makes it possible to get molecules having unpaired electrons and reversible electron donating/accepting nature. Using these molecules, we have been working to build bifunctional molecular materials with electrical and magnetic functions.



Molecular magnetic conductor: The conduction electrons are moving in the stack of planar shaped organic molecules and localized magnetic moments in the anions of magnetic coordination compounds are antiferromagnetically arranged (Left). Only one Co atom magnetizes all Pd atoms in Pd nanoparticle (single-particle magnet) (right)

Atmosphere of Laboratory

Staff members and students are active in many aspects; education, research, discussion, etc., even extra-laboratory activities. They are interactive with each other and also with outside research groups (domestic and in foreign countries) in their research works. They are working in the friendly atmosphere in the labs. We welcome those who are interested in challenging to develop interdisciplinary new fields in physical chemistry, material science, surface science, nanoscience and condensed matter physics.