Elastocaloric signatures of symmetric and antisymmetric strain-tuning of quadrupolar and magnetic phases in DyB₂C₂

Creators: Ye, Linda; Sun, Yue; Sunko, Veronika; Rodriguez-Nieva, Joaquin F.; Ikeda, Matthias S.; Worasaran, Thanapat; Sorensen, Matthew E.; Bachmann, Maja D.; Orenstein, Joseph; Fisher, Ian R.

Abstract

The adiabatic elastocaloric effect measures the temperature change of a given system with strain and provides a thermodynamic probe of the entropic landscape in the temperature-strain space. Here, we demonstrate that the DC bias strain-dependence of AC elastocaloric effect allows decomposition of the latter into symmetric (rotation-symmetry-preserving) and antisymmetric (rotation-symmetry-breaking) strain channels, using a tetragonal f-electron intermetallic DyB₂C₂ —whose antiferroquadrupolar order breaks local fourfold rotational symmetries while globally remaining tetragonal—as a showcase example. We capture the strain evolution of its quadrupolar and magnetic phase transitions using both singularities in the elastocaloric coefficient and its jumps at the transitions, and the latter we show follows a modified Ehrenfest relation. We find that antisymmetric strain couples to the underlying order parameter in a biquadratic (linear-quadratic) manner in the antiferroquadrupolar (canted antiferromagnetic) phase, which are attributed to a preserved (broken) global tetragonal symmetry, respectively. The broken tetragonal symmetry in the magnetic phase is further evidenced by elastocaloric strain-hysteresis and optical birefringence. Additionally, within the staggered quadrupolar order, the observed elastocaloric response reflects a quadratic increase of entropy with antisymmetric strain, analogous to the role magnetic field plays for Ising antiferromagnetic orders by promoting pseudospin flips. Our results demonstrate AC elastocaloric effect as a compact and incisive thermodynamic probe into the coupling between electronic degrees of freedom and strain in free energy, which holds the potential for investigating and understanding the symmetry of a wide variety of ordered phases in broader classes of quantum materials.

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Acknowledgement

We thank R.M. Fernandes and A.P. Mackenzie for fruitful discussions.

Funding

Experimental work performed at Stanford University was funded by the Gordon and Betty Moore Foundation EPiQS Initiative, grant GBMF9068. L.Y. also acknowledges support by the Marvin Chodorow Postdoctoral Fellowship at the Department of Applied Physics, Stanford University. M.D.B. acknowledges support by the Geballe Laboratory for Advanced Materials Fellowship. Optical measurements were performed at the Lawrence Berkeley Laboratory as part of the Quantum Materials program, Director, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, of the US Department of Energy under Contract No. DE-AC02-05CH11231. V.S. is supported by the Miller Institute for Basic Research in Science, UC Berkeley. J.O. and Y.S. received support from the Gordon and Betty Moore Foundation's EPiQS Initiative through Grant GBMF4537 to J.O. at UC Berkeley. J.F.R.-N. acknowledges support from the Gordon and Betty Moore Foundation's EPiQS Initiative through Grants GBMF4302 and GBMF8686.

Contributions

L.Y. and I.R.F. designed research; L.Y., Y.S., V.S., M.S.I., T.W., and M.D.B. performed research; L.Y., J.F.R.-N. and M.E.S. contributed new reagents/analytic tools; L.Y., Y.S., V.S., and J.O. analyzed data; and L.Y. and I.R.F. wrote the paper.

Data Availability

Spreedsheet data have been deposited in Stanford Digital Repository (https://doi.org/10.25740/wy533np2837) (36).

Conflict of Interest

The authors declare no competing interest.

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