Spin-orbit coupling studies of materials: some examples

DIPC Seminars

Speaker

Dr. Roberto Robles, ICN2

When

2018/04/20
14:00

Place

Donostia International Physics Center

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Spin-orbit coupling (SOC) plays a central role in the properties of many tech- nologically and fundamentally relevant materials. In the last years di erent phenomena have been predicted and discovered involving SOC. For example, SOC is crucial in the study of exotic magnetic properties, spintronics, and topological insulators. One of the most commonly studied consequences of SOC is the preferen- tial orientation of the magnetic moments along certain directions of the lattice: the magnetic anisotropy energy (MAE). We have studied MAE in low-dimensional systems consisting of heterogeneous transition metal chains supported on a Cu2N/Cu(100) surface [1]. MAE is also relevant in the study of materials for magnetic data storage. Conventionally these devices are controlled by magnetic elds generated by electric currents. To optimize the energy efficiency it is desirable to lower the magnetic elds needed to manipulate the devices. This can be achieved by lowering the coercivity of the material. Here we show the reduction of the coercivity in nanoporous Cu-Ni lms just by the action of an electric eld. By performing ab-initio calculations we o er some insight into the mechanisms behind the observed behavior [2]. Another interesting topic is the enhancement of spin-orbit interactions in materials with small intrinsic SOC, like graphene. One way of achieving this goal is the proximity with a material with strong intrinsic SOC, such as topo- logical insulators. We have studied the spin properties of Graphene/Bi2Se3 heterostructures, in particular the nontrivial spin-texture induced in the graphene states, and their possible implications on the spin transport prop- erties of the resulting system [3]. Finally, I will comment on recent advances of the treatment of SOC in the ab-initio DFT code Siesta. [1] D-J. Choi et al. Physical Review B 94, 085406 (2016) [2] A. Quintana et al. Advanced Functional Materials 27, 1701904 (2017) [3] K. Song et al. Nano Letters 18, 2033 (2018)