Cascade of magnetic field induced Lifshitz transitions in the ferromagnetic Kondo lattice material YbNi4P2

TL;DR

This study reveals nine magnetic field-induced Lifshitz transitions in YbNi4P2, a Kondo lattice material, highlighting its complex Fermi surface and the influence of its one-dimensionality on quantum critical behavior.

Contribution

First experimental identification of multiple Lifshitz transitions in YbNi4P2 using transport and thermodynamic measurements, shedding light on its Fermi surface topology.

Findings

Nine Lifshitz transitions observed between 0.4 and 18 T

Identification of neck and void type transitions

Unprecedented number of transitions due to flat renormalized band structure

Abstract

A ferromagnetic quantum critical point is thought not to exist in two and three-dimensional metallic systems yet is realized in the Kondo lattice compound YbNi4(P,As)2, possibly due to its one-dimensionality. It is crucial to investigate the dimensionality of the Fermi surface of YbNi4P2 experimentally but common probes such as ARPES and quantum oscillation measurements are lacking. Here, we studied the magnetic field dependence of transport and thermodynamic properties of YbNi4P2. The Kondo effect is continuously suppressed and additionally we identify nine Lifshitz transitions between 0.4 and 18 T. We analyze the transport coefficients in detail and identify the type of Lifshitz transitions as neck or void type to gain information on the Fermi surface of YbNi4P2. The large number of Lifshitz transitions observed within this small energy window is unprecedented and results from the particular flat renormalized band structure with strong 4f-electron character shaped by the Kondo lattice effect.