Abstract
The electronic property and magnetic susceptibility of Ce3Pd3Bi4 were systemically investigated from 18 to 290 K for varying values of cell volume using dynamic mean-field theory coupled with density functional theory. By extrapolating to zero temperature, the ground state of Ce3Pd3Bi4 at ambient pressure is found to be a correlated semimetal due to insufficient hybridization. Upon applying pressure, the hybridization strength increases and a crossover to the Kondo insulator is observed at finite temperatures. The characteristic temperature signaling the formation of Kondo singlet, as well as the characteristic temperature associated with f-electron delocalization–localization change, simultaneously vanishes around a critical volume of 0.992 V0, suggesting that such metal–insulator transition is possibly associated with a quantum critical point. Finally, Wilson’s loop calculations indicate that the Kondo insulating side is topologically trivial, thus a topological transition also occurs across the quantum critical point.
Highlights
Kondo insulator is a prototypical strongly correlated quantum matter involving 4f or 5f electrons
For the most compressed compound (90% V0) considered in this work, the energy gap can be identified at even higher temperature, implying the external pressure has driven the system away from the metallicity
It is worth noting that the spectra of 90% compressed Ce3Pd3Bi4 compound at 29 K resembles that of Ce3Pt3Bi4 at 18 K19, suggesting similar effect of external pressure and isoelectronic substitution by Pt, in agreement with the previous study[23]
Summary
Kondo insulator is a prototypical strongly correlated quantum matter involving 4f or 5f electrons. The system is metallic since the f-electron-derived local moments do not strongly couple to conduction electrons. According to the famous Doniach phase diagram[1], this coupling leads to a conduction-electron mediated Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction, which in turns competes with the Kondo coherence effect. They are characterized by respective energy scale, TRKKY and TK. Apart from temperature, the strength of hybridization can be tuned via chemical doping, external pressure and magnetic field alternatively. These nonthermal parameters provide control over competing ground states, and may realize quantum critical phenomena[2–4]. It has been proposed that the critical point of a topological quantum phase transition can host novel semimetal states, which exhibit nonFermi liquid or marginal Fermi-liquid behavior[5–8]
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