Charge Ordering and Magnetic Exchange in the Ladder-Type Compound NH₄V₂O₅

2025/08/19 by Korotin, Dm. M.
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Strongly Correlated Electrons (cond-mat.str-el)

paper · doi:10.48550/arxiv.2508.13519

Abstract

The low-temperature electronic and magnetic properties of NH₄V₂O₅, an isoelectronic analog of the spin-ladder compound α'-NaV₂O₅, are investigated using DFT+U calculations. Two charge-ordering patterns - zigzag and linear chains of V⁴⁺/V⁵⁺ ions - are considered. The zigzag configuration is found to be energetically preferred and exhibits insulating behavior with a band gap of 1.7 eV. In this state, magnetic V⁴⁺ (d¹) ions form antiferromagnetically coupled spin chains. Calculated exchange interactions reveal strong diagonal (intrarung) and interladder couplings, indicating a complex spin-ladder network. These results suggest that NH₄V₂O₅ retains essential spin-ladder characteristics while displaying new structural and magnetic features arising from the larger size and non-spherical geometry of the NH₄⁺ ion compared to Na⁺.

Citations

• Q<scp>uantum</scp> ESPRESSO toward the exascale
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