Non-Fermi liquid and Hund correlation in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>La</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mi>Ni</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>10</mml:mn></mml:msub></mml:mrow></mml:math> under high pressure
Jing-Xuan Wang, Zhenfeng Ouyang, Rong-Qiang He, Zhong-Yi Lu
Abstract
High temperature superconductivity was recently found in the bilayer nickelate ${\mathrm{La}}_{3}{\mathrm{Ni}}_{2}{\mathrm{O}}_{7}$ (La327), followed by the discovery of superconductivity in the trilayer ${\mathrm{La}}_{4}{\mathrm{Ni}}_{3}{\mathrm{O}}_{10}$ (La4310), under high pressure. Through studying the electronic correlation of La4310 with $\mathrm{DFT}+\mathrm{DMFT}$, and further comparing it with that of La327, we find that the ${e}_{g}$ orbitals of the outer-layer Ni cations in La4310 have a similar (but slightly weaker) electronic correlation to those in La327, in which the electrons behave as a non-Fermi liquid with Hund correlation and linear-in-temperature scattering rate. Our results suggest that the experimentally observed ``strange metal'' behavior may be explained by the Hund spin correlation featuring high spin states and spin-orbital separation. In contrast, the electrons in the inner-layer Ni cations in La4310 behave as a Fermi liquid. The weaker electronic correlation in La4310 is attributed to more hole doping, which may explain its lower superconducting transition temperature.