16. 02. 2023 D. Hovančík

Sizable orbital moment revealed in 2D magnets

Sizable orbital moment revealed in 2D magnets

Basic principle of the XMCD technique revealing the orbital momentum on Vanadium site.

Van der Waals materials exhibiting two-dimensional magnetism are an ideal platform for the on-demand engineering of multifunctional devices suitable for spintronics, quantum computing, etc. Magnetocrystalline anisotropy is considered a key ingredient of the long-range magnetic order in two dimensions. The ferromagnetic semiconductor VI3 has recently attracted large attention due to its huge anisotropy. It was an open question whether such strong anisotropy originates from a non-zero orbital moment of Vanadium ion.

We have demonstrate the existence of an unquenched orbital moment of Vanadium in VI3 resolving the long debate on this issue.

Our group focused on studying the orbital moment of Vanadium to solve this problem and explain the mechanism of connection of magnetic anisotropy with the electronic structure of VI3. We used a unique capability of the X-ray magnetic circular dichroism (XMCD) technique to determine the magnetic orbital moment component of V ions. Our XMCD results unambiguously proved the existence of an exceptionality large magnetic orbital moment component of 0.6 µB per V ion. In synergy with the density functional theory calculations, we proposed the V electronic ground state configuration and ascribed the origin of the strong magnetocrystalline anisotropy to the entanglement of the non-zero orbital and spin moment of V ion. Our ligand field multiplet simulations of XMCD spectra well match the scenario of two inequivalent V ion positions in VI3 structure present at low temperatures. The details of our study was recently published in the ACS Nano Letters journal.

Related publication

D. Hovančík, J. Pospíšil, K. Carva, V. Sechovský and C. Piamonteze, Large Orbital Magnetic Moment in VI3Nano Letters 23 (2023) 1175-1180.
doi: 10.1021/acs.nanolett.2c04045