Investigation of Quantum Effects in Quantum Magnetic Materials
일 시 : 2022년 04월 29일 금요일 16:00
연 사 : 도 승 환 박사 (Oak Ridge National Lab)
장 소 : 자연과학관 747호 & 온라인 ( 회의 ID: 893 6038 1750 , 암호: 164860 )
Quantum magnetism studies quantum effects manifested in magnetic properties created by the interplay of lattice, charge, orbital, and spin. The resulting quantum mechanical ‘spin states’ possess quantum fluctuations, quantum entanglements, quantum many-body effect, or topology of the quantum mechanical wave functions that are not accounted for by classical limit, realizing "quantum magnetic material". Significantly, such quantum materials are of great interest and are being actively studied in both fundamental study and future applications because they have great technological potential for a fault-tolerant quantum computing, quantum information sensor, and (magnon) spintronics.
In this talk, we study how to observe the quantum effects in quantum magnetic material examples, focusing on the Kitaev quantum spin model in α-RuCl3. The Kitaev honeycomb model provides a novel platform for quantum spin liquids, resulting from quantum fluctuations and quantum entanglement. As a result, a fractionalized Majorana fermion emerges as an elementary excitation. More importantly, this Majorana fermion becomes a non-abelian anyon in magnetic field, which is the key to realizing a topological quantum qubit for a quantum computing. This has stimulated many theoretical and experimental efforts on the materializations of Kitaev quantum spin liquids. In this talk, sample synthesis, physical properties, and inelastic neutron scattering measurements for α-RuCl3 are presented, and we discuss the quantum spin liquid state and Majorana fermion of the compound.