Abstract
The electronic structure of heavy-fermion materials is highly renormalised at low temperatures with localised moments contributing to the electronic excitation spectrum via the Kondo effect. Thus, heavy-fermion materials are very susceptible to Lifshitz transitions due to the small effective Fermi energy arising on parts of the renormalised Fermi surface. Here, we study Lifshitz transitions that have been discovered in YbNi_44P_22 in high magnetic fields. We measure the angular dependence of the critical fields necessary to induce a number of Lifshitz transitions and find it to follow a simple Zeeman-shift model with anisotropic g-factor. This highlights the coherent nature of the heavy quasiparticles forming a renormalised Fermi surface. We extract information on the orientation of the Fermi surface parts giving rise to the Lifshitz transitions and we determine the anisotropy of the effective gg-factor to be \eta \approx 3.8η≈3.8 in good agreement with the crystal field scheme of YbNi_44P_22.
Highlights
The electronic and magnetic properties of metals are in close relationship with the electronic structure at the Fermi level
Further theoretical scenarios to explain the existence of a FM quantum critical point (QCP) can arise for heavy-fermion materials like YbNi4P2 where the disintegration of quasiparticles has been predicted to lead to a FM QCP [10]
We study the electronic structure of heavy-fermion ferromagnet YbNi4P2 which has been shown to exhibit a FM QCP induced upon small substitution of phosphorus by arsenic [11] and which features one-dimensional chains of ytterbium atoms leading to quasi 1D Fermi surface sheets in unrenormalised band structure calculations [12]
Summary
The electronic and magnetic properties of metals are in close relationship with the electronic structure at the Fermi level. For clean metallic systems in dimensions larger than one, the coupling of fermionic excitations to any uniform magnetisation has been predicted to lead to a discontinuous ferromagnetic transition at low temperatures rendering the quantum phase transition discontinuous and removing low-energy quantum fluctuations [1, 9]. This theoretical framework leaves the possibility for one-dimensional systems to promote a FM QCP. This is achieved for magnetic field in the (001)-(100) plane
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call