Pressure-induced ferromagnetism in the topological semimetal EuCd${}_2$As${}_2$

Abstract

The antiferromagnet and semimetal EuCd${}_2$As${}_2$ has recently attracted a lot of attention due to a wealth of topological phases arising from the interplay of topology and magnetism. In particular, the presence of a single pair of Weyl points is predicted for a ferromagnetic configuration of Eu spins along the $c$-axis in EuCd${}_2$As${}_2$. In the search for such phases, we investigate here the effects of hydrostatic pressure in EuCd${}_2$As${}_2$. For that, we present specific heat, transport and $\mu$SR measurements under hydrostatic pressure up to $\sim 2.5$GPa, combined with {\it ab initio} density functional theory (DFT) calculations. Experimentally, we establish that the ground state of EuCd${}_2$As${}_2$ changes from in-plane antiferromagnetic (AFM${}_{ab}$) to ferromagnetic at a critical pressure of $\approx$2\,GPa, which is likely characterized by the moments dominantly lying within the $ab$ plane (FM${}_{ab}$). The AFM${}_{ab}$-FM${}_{ab}$ transition at such a relatively low pressure is supported by our DFT calculations. Furthermore, our experimental and theoretical results indicate that EuCd${}_2$As${}_2$ moves closer to the sought-for FM${}_c$ state (moments $\parallel$ $c$) with increasing pressure further. We predict that a pressure of $\approx$\,23\,GPa will stabilize the FM${}_c$ state, if Eu remains in a 2+ valence state. Thus, our work establishes hydrostatic pressure as a key tuning parameter that (i) allows for a continuous tuning between magnetic ground states in a single sample of EuCd${}_2$As${}_2$ and (ii) enables the exploration of the interplay between magnetism and topology and thereby motivates a series of future experiments on this magnetic Weyl semimetal.

arXiv comment8 figures in main text, 6 figures in Appendix; 14 pages total

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Cited by in corpus (16)

• Ab-initio overestimation of the topological region in Eu-based compounds
• Perspective on the muon-spin rotation/relaxation under hydrostatic pressure
• Colossal magnetoresistance in EuZn${}_2$P${}_2$ and its electronic and magnetic structure
• Consecutive topological phase transitions and colossal magnetoresistance in a magnetic topological semimetal
• Spin-carrier coupling induced ferromagnetism and giant resistivity peak in EuCd${}_2$P${}_2$
• The discovery of three-dimensional Van Hove singularity
• Carrier-induced transition from antiferromagnetic insulator to ferromagnetic metal in the layered phosphide EuZn${}_2$P${}_2$
• Manipulating magnetism and transport properties of EuCd${}_2$P${}_2$ with a low carrier concentration
• Absence of Weyl nodes in EuCd${}_2$As${}_2$ revealed by the carrier density dependence of the anomalous Hall effect
• Small moment antiferromagnetic ordering in single crystalline La2Ni7
• Pressure-induced ideal Weyl semimetal state in the layered antiferromagnet EuCd2As2
• Intrinsic insulating transport characteristics in low-carrier density EuCd2As2 films
• Influence of magnetism, strain and pressure on the band topology of EuCd${}_2$As${}_2$
• Absence of metallicity and bias-dependent resistivity in low-carrier-density EuCd2As2
• Revealing the EuCd_{2}As_{2} Semiconducting Band Gap via n-type La-Doping
• Recent advances in understanding and manipulating magnetic and electronic properties of Eu$M_2{X}_2$ ($M$ = Zn, Cd; $X$ = P, As)