“Computational Study of Magnetic Behaviour in Ni- Adsorbed Nb2C MXene using Density Functional Theory”

Abstract

2-dimensional metal carbides are freshly known as promising members, due to their encouraging applications. Among all the properties of MXene, their magnetic nature is researched vaguely in both experimental and theoretical fields. This property needs to be explored for the probable use in new upcoming applications such as spintronics and nano magnetic data storage devices. In the last 30 years, the quantum mechanical simulation of the cyclic systems has been done using density functional theory. Recently, it is widely used for the simulation of different structures and studying their electronic, optical, and magnetic properties. This thesis presents an insight to the magnetic properties of functionalized Nb2C MXene and its adsorbed compound Ni-Nb2C using Density Functional Theory. The Nb2C-OF and Ni-Nb2C-O-F are simulated using DFT implemented software Wien2k. A unit cell of Nb2C-O-F is simulated consisting of 4 atoms of Nb, 2 Carbon, 3 Oxygen atoms and 1 Fluorine atom. This unit cell simulated was further expanded in 2×2×1 supercell and optimized at about 500 k-points in the irreducible Brillouin zone. Similarly, 4 × 4 × 1 supercell is used to analyse the stable structure for Ni absorbed Nb2C-O-F. The analysis for the magnetic properties in done using exchange-correlational functionals spin-GGA and spin-GGA+U where for Nickel U= 6 eV. The band structure for both compounds is found to be metallic with zero band gap. The magnetic moment calculate for Nb2C-O-F is -0.00027 𝜇𝛽. Although the value is small but confirms it diamagnetic behaviour and superconductive nature. The magnetic moment calculated for Ni-Nb2C-O-F is +1.01516 𝜇𝛽 which shows that it is non-superconducting Ferromagnet. This switching of magnetic behaviour clearly shows that the adsorbent along with surface terminations had influenced the magnetic property of Nb2C-O-F.