Dresden 2020 – wissenschaftliches Programm
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TT 24.1: Vortrag
Dienstag, 17. März 2020, 09:30–09:45, HSZ 304
Low temperature thermal transport studies on the kagome quantum spin liquid candidate herbertsmithite — Jan Bruin, •Ralf Claus, Yosuke Matsumoto, Jürgen Nuss, Masahiko Isobe, and Hidenori Takagi — Max Planck Institute for Solid State Research, Stuttgart, Germany
Quantum spin liquids (QSLs) are a novel state of matter that may host exotic excitations like itinerant charge-neutral spin-1/2 quasiparticles (spinons). The prototype for a QSL ground state is the spin-1/2 Heisenberg antiferromagnet on the kagome lattice. In terms of materials, herbertsmithite (ZnCu3(OH)6C12) provides a perfect realization of this model. However, despite theoretical and experimental efforts the nature of its ground state remains under debate. An important question concerns the existence of an excitation gap.
To address this issue, we performed thermal transport measurements down to 80 mK. The measurement of the thermal conductivity (k) only captures mobile excitations in the material and is therefore a powerful tool to detect low-lying (gapless) spinons. In our measurements, we confirmed the absence of a finite k/T (spinon) term but observed a robust T-squared power-law behavior. I will discuss the possible QSL ground state scenarios in detail as well as an unusual field dependence.