"Symmetric and antisymmetric strain as continuous tuning parameters for electronic nematic order"

M. S. Ikeda: T. Worasaran, J. C. Palmstrom, J. A. W. Straquadine, P. Walmsley, and I. R. Fisher; Physical Review B, 02/21/18.

Additional Authors: T. Worasaran, J. C. Palmstrom, J. A. W. Straquadine, P. Walmsley, and I. R. Fisher

Abstract:

We report the separate response of the critical temperature of the nematic phase transition TS to symmetric and antisymmetric strains for the prototypical underdoped iron pnictide Ba(Fe0.975Co0.025)2As2. This decomposition is achieved by comparing the response of TS to in-plane uniaxial stress and hydrostatic pressure. In addition to quantifying the two distinct linear responses to symmetric strains, we find a quadratic variation of TS as a response to antisymmetric strains ɛB1g=1/2(ɛxxɛyy), exceeding the nonlinear response to symmetric strains by at least two orders of magnitude. These observations establish orthogonal antisymmetric strain as a powerful tuning parameter for nematic order.