Possible quantum nematic in a colossal magnetoresistance material

Abstract

EuB6 has for a long time captured the attention of the physics community, as it shows a ferromagnetic phase transition leading to a insulator the metal transition together with colossal magnetoresistance (CMR). EuB6 has a very low carrier density, which is known to drastically change the interaction between the localized Eu moments and the conduction electrons. One of early triumphs of the quantum theory in condensed matter was the presence of Fermi surface, which is intimately linked to the symmetry of the underlying crystal lattice. This symmetry can be probed by angle resolved magnetoresistance (AMRO) measurements. Here, we present angle resolved magnetoresistance (AMRO) measurements that show a that in EuB6 this symmetry is broken, possibly indicating the presence of a quantum nematic phase. We identify the region in the temperature-magnetic field phase diagram where the magnetoresistance shows two-fold oscillations instead of the expected fourfold pattern. Quantum nematic phases are analogous to classical liquid crystals. Like liquid crystals, which break the rotational symmetry of space, their quantum analogs break the point-group symmetry of the crystal due to strong electron-electron interactions, as in quantum Hall states, Sr3Ru2O7, and high temperature superconductors. This is the same region where magnetic polarons were previously observed, suggesting that they drive the nematicity in EuB6. This is also the region of the phase diagram where EuB6 shows a colossal magnetoresistance (CMR). This novel interplay between magnetic and electronic properties could thus be harnessed for spintronic applications.

6+5 pages. v2: added demagnetization analysis

References in corpus (10)

• Electronic liquid crystal state in the high-temperature superconductor YBCO(6.45)
• Formation of a Nematic Fluid at High Fields in Sr3Ru2O7
• Emergence of the nematic electronic state in FeSe
• Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn5
• Electrical resistivity near Pomeranchuk instability in two dimensions
• Nonlinear Hall effect as a signature of electronic phase separation in the semimetallic ferromagnet EuB6
• Magnetically-driven electronic phase separation in the semimetallic ferromagnet EuB${}_6$
• Time-reversal symmetry breaking driven topological phase transition in EuB${}_6$
• Angle dependent magnetoresistance measurements in Tl${}_2$Ba${}_2$CuO${}_{6+\delta }$ and the need for anisotropic scattering
• Lattice strain accompanying the colossal magnetoresistance effect in EuB${}_6$

Cited by in corpus (4)

• Intrinsic Magnetic Topological Materials
• Classification of electronic nematicity in three-dimensional crystals and quasicrystals
• Compatible Instability: Gauge Constraints of Elasticity Inherited by Electronic Nematic Criticality
• Magnetic domain structure and domain wall bound states of topological semimetal EuB6