Stress-induced multiple quantum phase transitions in the B1 and B2 phases of CeN

Release time:2024-03-08  Hits:

• Journal:Physical Review B
• Abstract:The quantum phase transition in Ce-based compounds has attracted significant attention in strongly correlated systems, primarily due to the dual nature of f electrons. Rare-earth nitride (Re-N) compounds are particularly intriguing, as they exhibit major physical mechanisms such as the Kondo effect or mixed-valence behavior. Notably, CeN is anomalously small in lattice parameter compared with other Re-N compounds and there is a structure phase transition from B1-type (NaCl-type) to B2− type (CsCl-type) at approximately 77 GPa. Hence, we study the electronic structures of B1-type and B2−type CeN by tuning stress, employing the DFT+DMFT method. Our results clarify the B1-type CeN is in a mixed-valence state at ambient pressure. However, as the system experiences compression and tension, CeN undergoes multiple quantum phase transitions, transitioning from a mixed-valence state to a Kondo metal and ultimately to an insulator. Importantly, it is observed that the number of occupied 4f electrons nf of Ce increases as the temperature and pressure increase within the mixed-valence regime, contrasting with the behavior observed in the Kondo regime, the nf is very stable, nearly one. Furthermore, we also investigate the high-pressure phase of B2-type CeN, it also presents mixed-valence and Kondo metal phases transition by tuning stress. Our paper illustrates stress as a clean method to tune quantum phase transitions in CeN by changing the states of f electrons and clarifying the physical driving force of phase transitions.
• Indexed by:Journal paper
• Translation or Not:no
• Date of Publication:2024-01-01
• Links to published journals:https://journals.aps.org/prb/abstract/10.1103/PhysRevB.109.125114