Quantum critical behaviour and Lifshitz transition in intermediate valence $\alpha$-YbAlB${}_4$

Abstract

Intermetallic compounds containing $f$-electron elements have been prototypical materials for investigating strong electron correlations and quantum criticality (QC). Their heavy fermion ground state evoked by the magnetic $f$-electrons is susceptible to the onset of quantum phases, such as magnetism or superconductivity, due to the enhanced effective mass ($m^{\ast }$) and a corresponding decrease of the Fermi temperature. However, the presence of $f$-electron valence fluctuations to a non-magnetic state is regarded an anathema to QC, as it usually generates a paramagnetic Fermi-liquid state with quasiparticles of moderate $m^{\ast }$. Such systems are typically isotropic, with a characteristic energy scale $T_0$ of the order of hundreds of kelvins that require large magnetic fields or pressures to promote a valence or magnetic instability. Here we show that the intermediate valence compound $\alpha$-YbAlB${}_4$ surprisingly exhibits both quantum critical behaviour and a Lifshitz transition under low magnetic field, which is attributed to the anisotropy of the hybridization between the conduction and localized $f$-electrons. These findings suggest a new route to bypass the large valence energy scale in developing the QC.

18 pages, 15 figures (3 panels)

References in corpus (14)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Quantum Criticality in Heavy Fermion Metals
• Quantum criticality
• Quantum Criticality
• Quantum Valence Criticality as Origin of Unconventional Critical Phenomena
• Characteristic signatures of quantum criticality driven by geometrical frustration
• Metamagnetic quantum criticality in Sr3Ru2O7 studied by thermal expansion
• Layered Kondo lattice model for quantum critical beta-YbAlB4
• β-YbAlB4: a critical nodal metal
• Grüneisen parameter studies on heavy fermion quantum criticality
• Model for Ferromagnetic Quantum Critical Point in a 1D Kondo Lattice
• Kondo hybridization and quantum criticality in $\beta$-YbAlB${}_4$ by laser-ARPES
• Ferromagnetic Quantum Critical Point Induced by Tuning the Magnetic Dimensionality of the Heavy-Fermion Iron Oxypnictide Ce(Ru${}_{1-x}$Fe${}_x$)PO
• Effect of Anisotropic Hybridization in YbAlB${}_4$ Probed by Linear Dichroism in Core-Level Hard X-ray Photoemission Spectroscopy

Cited by in corpus (1)

• Gapped Spin Excitation in Magnetic Ordered State on Yb-Based Zigzag Chain Compound YbAgSe2