# Topological Phase Transition in an Archetypal f-electron Correlated System: Ce

## TL;DR

This paper reveals a topological phase transition in elemental Ce associated with the gamma-alpha transition, driven by f-d band inversion and coherent 4f band formation, controllable by pressure.

## Contribution

It uncovers a topological phase transition in Ce linked to the gamma-alpha transition, demonstrating a pressure-controlled 'topology switch' in a Kondo system.

## Key findings

- Topological phase transition occurs in Ce during gamma-alpha transition.
- The transition is driven by f-d band inversion and 4f band formation.
- Pressure around 1 GPa can switch the topological state at room temperature.

## Abstract

A typical f-electron Kondo lattice system Ce exhibits the well-known isostructural transition, the so-called gamma-alpha transition, accompanied by an enormous volume collapse. Most interestingly, we have discovered that a topological-phase transition also takes place in elemental Ce, concurrently with the gamma-alpha transition. Based on the dynamical mean-field theory approach combined with density functional theory, we have unravelled that the non-trivial topology in alpha-Ce is driven by the f-d band inversion, which arises from the formation of coherent 4f band around the Fermi level. We captured the formation of the 4f quasi-particle band that is responsible for the Lifshitz transition and the non-trivial Z2 topology establishment across the phase boundary. This discovery provides a concept of 'topology switch' for topological Kondo systems. The 'on' and 'off' switching knob in Ce is versatile in a sense that it is controlled by available pressure (around 1 GPa) at room temperature.