Nature Nanotechnology
·
2015
·Vol. 10
·期 7
·608-613
·
IF 34.048
Li Likai,Ye Guo Jun,Tran Vy,Fei Ruixiang,Chen Guorui,Wang Huichao,Wang Jian,Watanabe Kenji,Taniguchi Takashi,Yang Li,Chen Xian Hui,Zhang Yuanbo
For decades, two-dimensional electron gases (2DEG) have allowed important experimental discoveries1,2 and conceptual developments in condensed-matter physics3. When combined with the unique electronic properties of two-dimensional crystals, they allow rich physical phenomena to be probed at the quantum level4,5. Here, we create a 2DEG in black phosphorus—a recently added member of the two-dimensional atomic crystal family6,7,8—using a gate electric field. The black phosphorus film hosting the 2DEG is placed on a hexagonal boron nitride substrate. The resulting high carrier mobility in the 2DEG allows the observation of quantum oscillations. The temperature and magnetic field dependence of these oscillations yields crucial information about the system, such as cyclotron mass and lifetime of its charge carriers. Our results, coupled with the fact that black phosphorus possesses anisotropic energy bands with a tunable, direct bandgap6,7,8,9,10,11,12,13,14,15, distinguish black phosphorus 2DEG as a system with unique electronic and optoelectronic properties.
研究领域:
凝聚态物理
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Tungsten
·
2020
·Vol. 2
·期 3
·251-260
·
IF 0
Liu Xiao-Lei,Wang Hong-Yuan,Su Hao,Yu Zhen-Hai,Guo Yan-Feng
The intriguing quasiparticles in solids, known as Dirac, Weyl, and Majorana fermions, etc. with properties akin to those theoretically predicted but never realized in high-energy physics, have excited intensive research activities in recent years. The transition metal dipnictides are attractive because of their extremely large magnetoresistance that is usually attributed to the carrier compensation effect. We briefly review herein the crystal growth, magneto-transport measurements, and theoretical studies of tantalum dipnictides TaAs 2 and TaP 2 , with the emphasis being put on discussion of the nontrivial topological states in both materials. The analysis of quantum oscillations of the magnetoresistance unveils nonzero Berry phase. The chiral negative longitudinal magnetoresistance further points to possible Weyl state, which was recently theoretically suggested as the result of the magnetic field-induced Zeeman splitting effect no matter how large the field is. The analysis of these intriguing behaviors could brush up our understanding about the family of materials and would be valuable for future work on investigating the magnetic field-induced topological phase transition in such semimetals.
研究领域:
凝聚态物理
·
材料科学
✓ 已验证
DOI
ADVANCED FUNCTIONAL MATERIALS
·
2021
·Vol. 31
·期 13
·2008116
·
IF 18.808
Li Yang,Hao Wu,Liang Zhang,Wenfeng Zhang,Luying Li,Tappei Kawakami,Katsuaki Sugawara,Takafumi Sato,Gaojie Zhang,Pengfei Gao,Younis Muhammad,Xiaokun Wen,Boran Tao,Fei Guo,Haixin Chang
The discovery of type-II Weyl semimetal states in layered transition metal dichalcogenides Td-WTe 2 indicates great potential for novel electronic, spintronic, and quantum devices. Theoretically, the interaction between the topological states and the magnetic ordered states of Td-WTe 2 enables the modulation of Weyl semimetal states by an external magnetic field. However, currently, ferromagnetism in layered Td-WTe 2 is still elusive and rarely observed. In this research, ferromagnetic order into WTe 2 using magnetic chromium (Cr) doping with a two-step Te flux strategy is introduced. The Curie temperature ( T c ) and the ferromagnetic moment are well tuned with a Cr doping concentration. The T c of the Cr-doped layered Td-WTe 2 could be regulated from 182 to 283 K, which is close to room temperature. The saturation magnetic moment could be changed from 2.26 to 4.20 emu g –1 , which is stronger than most values reported for these materials. Most intriguingly, the Cr-doped layered Td-WTe 2 single crystals still exhibit semimetallic behavior and they possess very large magnetoresistance with obvious Shubnikov de Haas (SdH) quantum oscillations and an anomalous Hall effect. The findings offer feasible ways to induce and tune ferromagnetic orders in layered Td-WTe 2 and thus to control its topological phase with external magnetic fields.
研究领域:
凝聚态物理
·
材料科学
·
自旋电子学
·
量子材料
·
拓扑物态
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）