engleski

Plastic deformation of a quantum material

Uniaxial stress in the elastic regime has recently emerged as an important tool to investigate and tune the properties of quantum materials. However, the effects of irreversible, plastic deformation beyond the elastic regime are virtually unexplored. In this talk, I will present our recent investigations of plastic deformation of a prominent quantum material – strontium titanate (STO) [1]. Crystals of STO are surprisingly ductile at ambient temperature, and can be plastically deformed to a large extent in compression. Using diffuse neutron and x-ray scattering, we show that the deformation leads to the appearance of large-scale self-organized dislocation structures, that strongly influence the electronic properties. Raman scattering reveals the presence of quantum-critical ferroelectric fluctuations, and the superconducting transition temperatures are significantly increased compared to undeformed samples. Within a simple model, we argue that the locally enhanced ferroelectric fluctuations lead to the increase of Tc. The results open a new direction in quantum materials research, with wide-ranging opportunities for tuning the electronic properties of a broad class of material systems.

Quantum materials, superconductivity, plastic deformation, ferroelectric, quantum criticality

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