Electronic Structure Study of Pr3Ni2O7 Based on Density Functional Theory

Abstract

In the study of superconducting materials, nickelates have attracted significant attention due to their crystal structures and electronic properties resembling those of infinite-layer cuprates. The phenomenon of superconductivity was first discovered in 1911 by Dutch physicist Heike Kamerlingh Onnes, who observed that mercury exhibited zero electrical resistance near absolute zero. Subsequently, scientists proposed the BCS theory, formulated by John Bardeen, Leon Cooper, and Robert Schrieffer in 1957, which successfully explained the microscopic mechanisms of superconductivity. In 1986, George Bednorz and Alex Müller discovered the high-temperature superconductor yttrium barium copper oxide (YBCO), which has a superconducting transition temperature as high as 92 K. Recently, the synthesis and study of nickelate materials, such as NdNiO₂ and Nd₀. ₈Sr₀. ₂NiO₂, have shown superconducting transition temperatures ranging from 9 to 15 K, and high-pressure treatment has significantly increased the superconducting temperature. These advancements suggest that nickelates may possess superconducting mechanisms similar to those of cuprates, making them a hot topic of research. We chose Pr₃Ni₂O₇ as our research subject and employed density functional theory to calculate its band structure, finding that the d-orbitals of Ni and O play a crucial role in conductivity, with a substantial number of available electronic states for conduction.