2020/06/08 by Gergely Barcza, Viktor Ivády, Barcza, Gergely +11 · 3 citations
Physics and Astronomy · #Advanced Chemical Physics Studies #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena
paper · pdf · doi:10.48550/arxiv.2006.04557
In this paper, we analyze the numerical aspects of the inherently\nmulti-reference density matrix renormalization group (DMRG) calculations on top\nof the periodic Kohn-Sham density functional theory (DFT) using the complete\nactive space (CAS) approach. Following the technical outline related to the\ncomputation of the Hamiltonian matrix elements and to the construction of the\nactive space, we illustrate the potential of the framework by studying the\nvertical many-body energy spectrum of hexagonal boron nitride (hBN) nano-flakes\nembedding a single boron vacancy point defect with prominent multi-reference\ncharacter. We investigate the consistency of the DMRG energy spectrum from the\nperspective of sample size, basis size, and active space selection protocol.\nResults obtained from standard quantum chemical atom-centered basis\ncalculations and plane-wave based counterparts show excellent agreement.\nFurthermore, we also discuss the spectrum of the periodic sheet which is in\ngood agreement with extrapolated data of finite clusters. These results pave\nthe way toward applying DMRG method in extended correlated solid state systems,\nsuch as point qubit in wide band gap semiconductors.\n