Spontaneous Hall effect induced by strain in Pr${}_2$Ir${}_2$O${}_7$ epitaxial thin films

Abstract

Strongly correlated iridate pyrochlores with geometrically frustrated spins have been recognized as a potentially interesting group of oxide materials where novel topological phases may appear. A particularly attractive system is the metallic Pr${}_2$Ir${}_2$O${}_7$, as it is known as a Fermi node semimetal characterized by quadratic band touching at the Brillouin zone center, suggesting that the topology of its electronic states can be tuned by moderate lattice strain. In this work we report the growth of epitaxial Pr${}_2$Ir${}_2$O${}_7$ thin films grown by solid-state epitaxy. We show that the strained parts of the films give rise to a spontaneous Hall effect that persists up to 50 K without having spontaneous magnetization within our experimental accuracy. This indicates that a macroscopic time reversal symmetry (TRS) breaking appears at a temperature scale that is too high for the magnetism to be due to Pr 4$f$ moments, and must thus be related to magnetic order of the iridium 5$d$ electrons. The magnetotransport and Hall analysis results are consistent with the formation of a Weyl semimetal state that is induced by a combination of TRS breaking and cubic symmetry breaking due to lattice strain.

arXiv comment7 pages, 4 figures

References in corpus (11)

• Electronic Structure of Pyrochlore Iridates: From Topological Dirac Metal to Mott Insulator
• Topological Hall effect in the A-phase of MnSi
• Mott physics and band topology in materials with strong spin-orbit interaction
• Quantum Hall effects in a Weyl Semi-Metal: possible application in pyrochlore Iridates
• Non-Fermi liquid and topological states with strong spin-orbit coupling
• Topological insulators and metal-insulator transition in the pyrochlore iridates
• Quadratic Fermi Node in a 3D Strongly Correlated Semimetal
• Pressure Tuned Insulator to Metal Transition in Eu${}_2$Ir${}_2$O${}_7$
• All-in all-out magnetic order and propagating spin-waves in Sm2Ir2O7
• Anisotropic hysteretic Hall-effect and magnetic control of chiral domains in the chiral spin states of Pr${}_2$Ir${}_2$O${}_7$
• Unstable Spin-Ice Order in the Stuffed Metallic Pyrochlore Pr${}_{2+x}$Ir${}_{2-x}$O${}_{7-\delta }$

Cited by in corpus (2)

• Dielectric anomalies and interactions in the 3D quadratic band touching Luttinger semimetal Pr${}_2$Ir${}_2$O${}_7$
• Suppression of long range magnetic ordering and electrical conduction in Y${}_{1.7}$Bi${}_{0.3}$Ir${}_2$O${}_7$ thin film