“Emergent exotic quasiparticles in quantum spin liquids”

Prof. Y. Matsuda

Department of Physics, Kyoto University

Nov. 8 (Wed.), 1:00 PM

#5318 (E6-2. 5th fl.)

Quantum spin liquid (QSL) is an exotic quantum phase of matter whose ground state is quantum-mechanically entangled without any magnetic ordering. A central, yet poorly understood issue concerns the excitations that characterize QSLs, which are hypothetically associated with the quasiparticle fractionalization and topological order. It is widely believed that in dimensions more than one, geometrical frustrations are required to realize QSL states. Here I discuss emergent exotic quasiparticles of three types of QSL states in frustrated quantum magnets mainly by thermal transport measurements. 

1) Spinon excitations in organic Mott insulator EtMe₃Sb[Pd(dmit)₂]₂ and 1T-TaS₂ with triangular lattice.

2) Magnetic monopole (M-particle), electric monopole (E-particle), and photon (n-particle) excitations in rare earth pyrochlore oxides, Yb₂Ti₂O₇ and  Pr₂Zr₂O₇, both of which host spin-ice correlations with strong quantum fluctuations. 

3) Majorana fermion excitations and the half integer thermal Hall effect in a Kitaev QSL state on honeycomb lattice of a-RuCl₃

Contact: Eun Gook Moon, Physics Dept., (egmoon@kaist.ac.kr)

20171108_Prof.Yuji Matsuda.pdf