Maletinsky, Patrick
Date: Thursday, June 20, 2019
Time: 14:00
Place: ETH Zurich, Hönggerberg, HPF G 6
Host: Ataç İmamoğlu
Quantum sensing of atomically thin magnets
Patrick Maletinsky
Basel University, Switzerland
The recent discovery of long-range magnetic order in atomically thin "van der Waals’" crystals [1] has attracted significant attention due to its fundamental interest and technological potential [2]. Van der Waals (vdW) magnets exhibit a wide range of magnetic phases, may host exotic spin-textures and offer unique opportunities to control magnetism by gating or by materials-engineering through stacking of unlike vdW materials.
Key to such further progress is the possibility to address magnetic order in vdW magnets on the nanoscale, even in the few-layer limit – a requirement that no existing sensing or imaging technology has demonstrated thus far. I will present our recent results, where we employ a single spin-based nanoscale quantum sensor to overcome this limitation and address atomically thin vdW magnets with nanoscale resolution and in a quantitative way. Specifically, I will describe experiments, where we employed a diamond-based quantum sensor [3][4] to address magnetism in the prototypical vdW magnet chromium(III) iodide (CrI3) [5]. Our approach enabled quantitative, nanoscale imaging of magnetization patterns of CrI3 down to the level of mono- and few-layer thin crystals. By combining Raman spectroscopy and single spin magnetometry on the same few-layer crystals, we further revealed a delicate interplay between magnetic and crystalline (stacking) order, which appears ubiquitous for Cr-based vdW magnets and whose further control and understanding will be central for the development of vdW magnets into reliable spintronics devices.
Our results showcase the power of our quantum sensing technology [3][4] and offers attractive perspectives for future studies of few-layer vdW magnets. Advanced quantum sensing protocols, for example, could be employed to locally probe spindynamics these materials. Amongst other things, this could yield experimental evidence [6] for the still elusive quantum spin liquid phase which is believed to be present in certain vdW crystals down to the atomic monolayer limit [7].
References
[1] B. Huang et al., Nature 546, 270; C. Gong et al, ibid 265 (2017)
[2] M. Gibertini et al., Nature Nano. 14, 408 (2019)
[3] L. Rondin et al., Rep. Prog. Phys. 77 056503 (2014)
[4] P. Appel et al., Rev. Sci. Instr. 87, 063703 (2016)
[5] L. Thiel et al., Science 364, 973 (2019)
[6] S. Chatterjee et al., Phys. Rev. B 99, 104425 (2019)
[7] A. Banerjee et al., Science 356, 1055 (2017)