Physics CM/BIO/ECE Seminar Series Presents: Yiyao Chen

Wednesday, April 11, 2018 4:00pm

Room 223A, Physics Building Library



Yiyao Chen

The MU Physics & Astronomy Department’s Condensed Matter - Biological Physics - Electrical & Computer Engineering seminar series presents, "Quantum Fluctuation due to Artificial Spin-1/2 in Perovskite," by Yiyao Chen, a postdoctoral fellow in physics, Wednesday, April 11 at 4:00 p.m. Refreshments will be served beginning at 3:30 p.m.

Chen writes, "Geometrically frustrated systems of Spin-1/2 ion provide a unique platform to study the novel phenomena of quantum spin liquid and local critical behavior. In this talk, we demonstrate the quantum magnetic properties of geometrically frustrated lattice of spin-1/2 magnet in a perovskite system where frustration is induced by controlled chemical disorder. The chemical substitution of Ru-ion by Co-ion in CaRuO3 perovskite creates a random configuration of artificial spin-1/2’s, that form dimer pairs with varying exchange energy. As the system crosses over into the insulating regime at Co-substitution of ~15%, a coexistence of quantum continuum fluctuation emerges, with extremely local spin dynamics and a weak spin glass order. For further increase in the substitution coefficient, the continuum fluctuation evolves into the localized excitation, manifesting a singlet-to-triplet excitation without any ordered spin correlation to the dispersive dynamic correlation. The localized gapped excitation in the insulating regime evolves into a gapless quasi-continuum, as dimer pairs break and create freely fluctuating fractionalized spins at high temperature. Our results hint of a new paradigm to the exploration of novel quantum magnetism of liquid-like spin correlation."