Physicochemical Soft Matter Research Team

Principal Investigator

PI Name Fumito Araoka
Degree Ph.D
Title Team Leader
Brief Resume
2003Ph.D. in Engineering, Tokyo Institute of Technology, Japan
2003Postdoctoral Researcher, Catholic University of Leuven, Belgium
2005Postdoctoral Researcher, The University of Tokyo
2006Postdoctoral Researcher, Tokyo Institute of Technology
2007Assistant Professor, Tokyo Institute of Technology
2013Unit Leader, Physicochemical Soft-Matter Research Unit, Cross-Divisional Materials Research Program, RIKEN Center for Emergent Matter Science
2018Team Leader, Physicochemical Soft-Matter Research Team, RIKEN Center for Emergent Matter Science (-present)


Our team is mainly working on functionality of soft-matter systems from the viewpoints of physical experiments and analyses. In our research unit, particular attention is paid to liquid crystals due to their self-organizability leading to multifarious structures in which many interesting physical phenomena emerge. Our interest also covers potential applications of such soft-matter systems towards optical/electronic or chemical devices. For example, 1. Ferroelectric interactions and switching mechanisms in novel liquid crystalline ferroelectric materials, 2. Chirality related phenomena - origin and control of emergence, as well as applications of superstructure chirality in self-organized soft-matter systems, 3. Novel optical/electronic devices based on self-organized soft-matter systems.

Research Fields

Physical and Structural Properties of Functional Organic Materials


Liquid crystals
Polymeric materials
Soft-matter physics
Optical properties
Organic nonlinear optics
Organic ferroelectrics


Topology-dependent Lehmann rotation in chiral nematic emulsions

Lehmann rotation is a ‘heat flow’-to-‘motion’ energy conversion effect in liquid crystals, which was found in the end of the 19th century. In spite of the huge effort by physicists for more than 100 years, its physical mechanism has not been clear yet. On the other hand, topology is ubiquitous in liquid crystals which can be treated as continua to understand many other complex physical systems. In this research, it was proven that highly efficient Lehmann rotation is realizable even in emulsion states of a chiral liquid crystal dispersed in a fluorinated oligomer, in which topological diversity is confirmed depending on the droplet size and the strength of chirality. Interestingly, the estimated heat-rotation conversion rate therein significantly depends on these inner topological states of the droplets. This result is not merely important as a key to solve the long-persistent physical problem in Lehmann rotation, but also interesting for fundamental sciences related to topology.

(A) Topological diversity in a chiral nematic emulsion, (B) Lehmann rotation depending on the topological states.


Fumito Araoka

Team Leader fumito.araoka[at] R

Satoshi Aya

Special Postdoctoral Researcher

Haruna Sasaki

Postdoctoral Researcher



2-1 Hirosawa, Wako, Saitama 351-0198 Japan