Advanced Seminar on Condensed Matter Physics (AG Klingeler)

Sommersemester 2023

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INF 227, SR 1.403
Friday 11:00

11.7.2023 10:00
Prof Kwang-yong Choi, Department of Physics, Sungkyunkwan University, Republic of Korea
INF 227, tba
The spin-1/2 antiferromagnetic Heisenberg model on a Kagomé lattice offers an excellent framework for investigating complex quantum entangled states. In particular, it allows for the exploration of a quantum spin liquid in the absence of an external field, as well as magnetic analogs of liquid, solid, and supersolid phases near magnetization plateaus. In this talk, we will address the experimental realization of these predicted novel phases in the material YCu3(OD)6+xBr3-x (x≈0.5) on a Kagomé lattice.
By combining thermodynamic and Raman spectroscopic techniques, we provide compelling evidence for the existence of fractionalized spinon excitations in YCu3(OD)6+xBr3-x (x≈0.5). These excitations exhibit a Dirac nodal structure, although their spectral weight at low energies is modified by the presence of bond randomness. Our preliminary NMR data reveal an inhomogeneous ground state due to inevitable perturbations. More significantly, we observe the 1/9 magnetization plateau at an accessible field range of μ0H1/9=15-21 T undiscovered hitherto in S=1/2 Kagomé antiferromagnets. Our findings highlight the significance of YCu3(OD)6+xBr3-x as a model material, which enables the investigation of field-induced quantum entangled states within the 1/9 plateau phase.