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TT: Fachverband Tiefe Temperaturen
TT 9: f-Electron Systems and Heavy Fermions II
TT 9.6: Talk
Monday, March 27, 2023, 16:15–16:30, HSZ 201
Strain-tuning of charge frustration in the heavy 3d fermion oxide LiV2O4 — •Ryosuke Oka1, 2, Dennis Huang1, Minu Kim1, Peter Wochner1, and Hidenori Takagi1, 2, 3 — 1Max Planck Institute for Solid State Research, Stuttgart, Germany — 2Department of Physics, University of Tokyo, Tokyo, Japan — 3Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Stuttgart, Germany
The mixed-valent spinel LiV2O4 is the first discovered 3d electron system showing heavy fermion behavior without localized f moments, but its origin has remained a decades-old mystery. Amongst numerous scenarios proposed so far, including an analogy with a dense Kondo system, one of the leading scenarios is charge frustration inherent in the pyrochlore sublattice of the spinel. In this scenario, the ground state is composed of a macroscopic number of degenerate charge orderings (COs), and the frustration prevents the system from undergoing a metal-to-insulator transition, thereby enhancing the effective mass. By applying external perturbations that lift the degeneracy in different ways, various insulating COs can be selected out of the frustrated metallic ground state. For example, hydrostatic pressure and biaxial tensile strain in the (001) plane stabilize distinct [111]- and [001]-oriented COs, respectively. We have grown LiV2O4 thin films on various substrates, in order to apply uniaxial strain in different directions. We used synchrotron x-ray diffraction to characterize the applied strain and transport measurements to probe how the heavy fermion phase in LiV2O4 moves toward possible distinct charge-ordered states.