发布日期:2018-09-25 作者:理学院


报告题目:Interlayer engineering in tuning physical properties of two-dimensional materials

报 告 人:季威  优青/青年长江学者



报告地点:龙赛理科楼 116


Van der Waals forces were believed dominant for interlayer interactions in layered two-dimensional (2D) materials. We recently found an emergent type of interlayer interactions, namely covalent-like quasi-bonding (CLQB) [1,2], in various 2D materials like black phosphorus [1,2], PtS2 [3], PtSe2 [4] and Te [5] few-layers. The existence of CLQB in Te allows to tune various Te phases from its bulk form (the alpha-phase) upon charge doping or external strain [6]. In addition to the known beta and gamma phases, At least three new phases, namely, delta, epsilon and zeta phases was found during charge doping and sliding of layers [7]. Among these phase, the alpha to gamma phases are semiconducting and the rest are metallic. In light of this, it might be a promising strategy to build all-Te electrical devices, since Te has both semiconducting and metallic phases, which show considerable stability and rather high carrier conductance. In addition, we discussed the interlayer magnetic couplings (IMC) of CrS2 and CrI3 bilayers. It is interesting that these two materials are at two extremes of IMC. The interlayer FM coupling in CrS2 is very robust and is nearly unable to be tuned under usual external fields, but the intra-layer magnetism does be varied under layer stacking [8]. An opposite case was found in CrI3 bilayers [9] where the intra-layer FM coupling is, however, very strong but the interlayer magnetism was found governed by a subtle change of interlayer stacking; this shows a decoupled magnetic interaction between intra- and inter-layer directions.


[1] J. Qiao et al. Nature Communications 5, 4475 (2014)

[2] Z.-X. Hu et al. Nanoscale 8, 2740 (2016).

[3] Y. Zhao et al. Advanced Materials 28, 2399-2407 (2016).

[4] Y. Zhao et al. Advanced Materials 29, 1604230 (2017).

[5] J. Qiao et al. Science Bulletin 63, 159-168 (2018).

[6] C. Wang, et al. arXiv:1806.06550

[7] C. Wang and L. Zhou et al. in preparation.

[8] C. Wang, et al. Phys. Rev. B 97, 245409 (2018), arXiv:1706.10213   

[9] P. Jiang and C. Wang et al. arXiv:1806.09274