Proximity-Induced Phenomena in Designer van der Waals Heterostructures

The atomically thin nature of 2D materials opens exciting possibilities for designing van der Waals heterostructures through proximity effects arising from short-range interactions [1]. These heterostructures offer a versatile platform for customizing electrical, magnetic, optical, and spin transport properties, making them highly suitable for advanced spintronic applications [1,2]. The interplay between thin layers of magnetic and non-magnetic materials at their interfaces is particularly crucial for these functionalities. For example, hexagonal transition metal dichalcogenides such as WS₂ can induce valley-Zeeman spin-orbit coupling (SOC) in graphene, leading to spin lifetime anisotropy between in-plane and out-of-plane spin orientations [3] and spin Hall and inverse spin galvanic effects [4]. However, the inherent threefold symmetry of these materials often results in isotropic in-plane spin dynamics [5].<br/><br/>In our recent work, we demonstrate that low-symmetry heterostructures can induce unprecedented gate-tunable SOC in graphene, leading to remarkable modulation of the spin lifetime for in-plane spins at room temperature [6]. Such heterostructures also enable the generation of unconventional charge-to-spin conversion components [7].<br/><br/>In this presentation, I will discuss our approach to demonstrate proximity effects through spin transport dynamics, with a focus on spin relaxation anisotropy and charge-to-spin interconversion [8,9]. I will highlight the crucial role of crystal symmetry and how reduced-symmetry systems can lead to unconventional spin-orbit fields that influence these phenomena, providing new insights into the design and engineering of next-generation spintronic devices.<br/><br/><b>Acknowledgements: </b><br/>This research was supported by MICIU/AEI/10.13039/501100011033 through Grant No. PID2022-143162OB-I00.<br/><br/><b>References</b><br/>[1] J. F. Sierra <i>et al</i>., <i>Nature Nano</i>. <b>16</b>, 856–868 (2021)<br/>[2] H. Yang, S O. Valenzuela <i>et al</i>., <i>Nature</i> <b>606</b>, 663-673 (2022)<br/>[3] L. A. Benítez <i>et al</i>., <i>Nature Phys</i>. <b>14</b> (2018); <i>APL Materials</i> <b>7</b>, 120701 (2019)<br/>[4] L. A. Benítez <i>et al</i>., <i>Nature Mater</i>. <b>19</b>, 170 (2020)<br/>[5] M. Milivojević, <i>et al</i>., <i>arXiv:</i><i>2402.09045</i> (2024)<br/>[6] J. F. Sierra, J. Světlík, <i>et al. unpublished </i>(2024)<br/>[7] L. Camosi <i>et al.</i>, <i>2D Mater</i>. <b>9,</b> 035014 (2022)<br/>[8] B. Raes <i>et al., Nature Commun</i>. <b>7</b>, 11444 (2016)<br/>[9] W. Savero Torres <i>et al.</i>, <i>2D Mater</i>. 4<b>,</b> 041008 (2017)