Sophie Rodehutskors
Flexoresistance: How to Bend Your Single Crystals
Uniaxial strain has been demonstrated as a tuning parameter for ground state transitions in quantum materials, including single crystals [1-3]. Using focused ion beam (FIB) machining, free-standing cantilevers can be extracted from single crystals along a chosen crystallographic orientation, allowing strain to be applied along a chosen symmetry channel of a material. Going beyond uniaxial strain, I will introduce a technique for applying a strain gradient along a cantilever’s cross-section by bending, implying the formation of different strain-tuned states within a single crystal. Recent developments in the FIB fabrication of bending samples have enabled the direct measurement of the electronic properties perpendicular to the gradient, including the Hall coefficient. As an example, I will show flexoresistance results on the iron-pnictide BaFe2(As1-xPx)2, which has been shown to be affected analoguously by strain and doping [3], and which shows a large response to the applied strain gradient.
References
[1] P. Malinowski et al., Suppression of Superconductivity by Anisotropic Strain near a Nematic Quantum Critical Point, Nat. Phys., 16(12) (2010) 1189-93.
[2] Kuo, H. H., et al., Magnetoelastically coupled structural, magnetic, and superconducting order parameters in
BaFe2(As1 − xPx )2, Phys. Rev. B 86(13) (2012), 134507.
[3] Böhmer, A. E., P. Burger, F. Hardy, et al. Thermodynamic Phase Diagram, Phase Competition, and Uniaxial Pressure Effects in BaFe 2 (As 1 − x P x ) 2 Studied by Thermal Expansion. Phys. Rev. B 86(9) (2012), 094521.