Role of on-site and intersite Coulomb interactions in KV3Sb5: A first-principles DFT plus U plus V study

초록

Nonlocal Coulomb interactions play a crucial role in stabilizing distinct electronic phases in kagome materials. In this work, we systematically investigate the effects of on-site (U) and intersite (V ) Coulomb interactions on the electronic structure and stability of charge-density-wave (CDW) phases in the kagome metal KV3Sb5 using density functional theory (DFT+U+V) calculations. We demonstrate that V promotes the formation and stability of CDW phases, whereas U suppresses these phases, highlighting a fundamental competition between local and nonlocal Coulomb interactions. By directly comparing our theoretical results with angle-resolved photoemission spectroscopy (ARPES) data, we identify realistic values of U and V that accurately describe the electronic band structure of KV3Sb5. Our findings establish a detailed U-V phase diagram for KV3Sb5, offering valuable insights into the correlated electronic states in kagome metals and serving as a foundation for future explorations of correlation-driven phenomena in related materials.

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