澳門皇冠官網

K

重點欄目

EY SECTIONS

澳門皇冠官網

理學院數理講壇(2018年第39講)

發布日期:2018-09-25 作者:理學院

理學院數理講壇2018年第39講)

報告題目:Interlayer engineering in tuning physical properties of two-dimensional materials

報 告 人:季威 ?優青/青年長江學者

??? 位:中國人民大學

報告時間:2018928日(星期五9:00

報告地點:龍賽理科樓 116

報告摘要:

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.

References:

[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

報告人簡介:

??季威博士長期專注于發展和應用獨特的第一性原理計算方法,研究了多種表面量子系統和信息材料與器件界面等領域的前沿問題。他最近的研究興趣主要集中在二維材料多種物性的理論模擬和調控策略方面。同時,他也在發展一些理論方法用于描述透射電子顯微鏡中的射線效應和非接觸原子力顯微鏡中的高分辨成像機理。季威博士于20083月在中國科學院物理研究所獲得博士學位,從2006年起在麥吉爾大學物理系做訪問學者和博士后研究,隨后于2010年加入中國人民大學物理系任副教授,并在2014年晉升教授。目前,他已經發表論文80余篇,被引3000余次,包括9ESI高被引論文和2ESI熱點論文。這些研究成果入選2013中國科學十大進展、2014年、2015年中國百篇最具影響國際學術論文。此外,他2011年入選了澳門皇冠新世紀優秀人才支持計劃、當選中國材料研究學會青委會理事;2014年入選中組部“萬人計劃”青年拔尖人才;2015年入選澳門皇冠長江學者獎勵計劃青年學者;2016年獲得優秀青年科學基金支持、擔任中國材料研究學會計算材料專業委員會委員。

福彩三d