稀磁半导体兼具半导体材料和磁性材料的双重特性,是破解摩尔定律难题的方案之一.我们团队通过提出自旋和电荷分别掺杂的机制,研制发现了一类新型稀磁半导体材料,为突破经典稀磁半导体材料自旋和电荷一体掺杂引起的材料制备瓶颈提供了有...稀磁半导体兼具半导体材料和磁性材料的双重特性,是破解摩尔定律难题的方案之一.我们团队通过提出自旋和电荷分别掺杂的机制,研制发现了一类新型稀磁半导体材料,为突破经典稀磁半导体材料自旋和电荷一体掺杂引起的材料制备瓶颈提供了有效解决方案.(Ba,K)(Zn,Mn)2As2(BZA)等新型稀磁半导体通过等价掺杂磁性离子引入自旋、异价非磁性离子掺杂引入电荷,实现了 230 K 的居里温度,刷新了可控型稀磁半导体的居里温度记录.本文重点介绍 1)几种代表性的自旋和电荷掺杂机制分离的新型稀磁半导体的发现与研制;2)新型稀磁半导体的子自旋弛豫与高压物性结构的调控;3)大尺寸单晶生长、基于单晶的安德烈夫异质结研制以及自旋极化率的测量.通过新材料设计研制、综合物性研究、简单原型器件构建的“全链条”模式研究,开拓了自旋电荷分别掺杂的稀磁半导体材料研究领域,展现了这类新型稀磁半导体材料潜在的光明前景.展开更多
The pressure effect on the crystalline structure of the I-II- V semiconductor Li（Zn,Mn）As ferromagnet is studied using in situ high-pressure x-ray diffraction and diamond anvil cell techniques. A phase transition st...The pressure effect on the crystalline structure of the I-II- V semiconductor Li（Zn,Mn）As ferromagnet is studied using in situ high-pressure x-ray diffraction and diamond anvil cell techniques. A phase transition starting at -11.6GPa is found. The space group of the high-pressure new phase is proposed as Pmca. Fitting with the Birch-Murnaghan equation of state, the bulk modulus B0 and its pressure derivative B0 of the ambient pressure structure with space group of F43m are B0 = 75.4 GPa and B0 = 4.3, respectively.展开更多
The layered semiconductor BaFZnAs with the tetragonal ZrCuSiAs-type structure has been successfully synthesized.Both the in-situ high-pressure synchrotron x-ray diffraction and the high-pressure Raman scattering measu...The layered semiconductor BaFZnAs with the tetragonal ZrCuSiAs-type structure has been successfully synthesized.Both the in-situ high-pressure synchrotron x-ray diffraction and the high-pressure Raman scattering measurements demonstrate that the structure of BaFZnAs is stable under pressure up to 17.5 GPa at room temperature. The resistivity and the magnetic susceptibility data show that BaFZnAs is a non-magnetic semiconductor. BaFZnAs is recommended as a candidate of the host material of diluted magnetic semiconductor.展开更多
Chemical pressure induced by iso-valent doping has been widely employed to tune physical properties of materials. In this work, we report effects of chemical pressure by substitution of Sb or P into As on a recently d...Chemical pressure induced by iso-valent doping has been widely employed to tune physical properties of materials. In this work, we report effects of chemical pressure by substitution of Sb or P into As on a recently discovered diluted magnetic semiconductor(Ba,K)(Zn,Mn)_2 As_2, which has the record of reliable Curie temperature of 230 K due to independent charge and spin doping. Sb and P are substituted into As-site to produce negative and positive chemical pressures, respectively.X-ray diffraction results demonstrate the successful chemical solution of dopants. Magnetic properties of both K-underdoped and K-optimal-doped samples are effectively tuned by Sb-and P-doping. The Hall effect measurements do not show decrease in carrier concentrations upon Sb-and P-doping. Impressively, magnetoresistance is significantly improved from7% to 27% by only 10% P-doping, successfully extending potential application of(Ba,K)(Zn,Mn)_2 As_2.展开更多
A new compound with one-dimensional spin chains, Ba9Co3Se(15), was synthesized under high pressure and high temperature conditions and systematically characterized via structural, transport and magnetic measurements. ...A new compound with one-dimensional spin chains, Ba9Co3Se(15), was synthesized under high pressure and high temperature conditions and systematically characterized via structural, transport and magnetic measurements. Ba9Co3Se(15) crystallizes in a hexagonal structure with the space group P-6c2(No. 188) and lattice constants of a = b = 9.6765 ? and c = 18.9562 ?. The structure consists of trimeric face-sharing octahedral CoSe6 chains, which are arranged in a triangular lattice in the ab-plane and separated by Ba atoms. The distance of the nearest neighbor of CoSe6 chains is very large, given by the lattice constant a = 9.6765 ?. The Weiss temperature Tθ associated with the intra-chain coupling strength is about -346 K. However, no long-range magnetic order but a spin glass transition at ~ 3 K has been observed. Our results indicate that the spin glass behavior in Ba9Co3Se(15) mainly arises from the magnetic frustration due to the geometrically frustrated triangular lattice.展开更多
文摘稀磁半导体兼具半导体材料和磁性材料的双重特性,是破解摩尔定律难题的方案之一.我们团队通过提出自旋和电荷分别掺杂的机制,研制发现了一类新型稀磁半导体材料,为突破经典稀磁半导体材料自旋和电荷一体掺杂引起的材料制备瓶颈提供了有效解决方案.(Ba,K)(Zn,Mn)2As2(BZA)等新型稀磁半导体通过等价掺杂磁性离子引入自旋、异价非磁性离子掺杂引入电荷,实现了 230 K 的居里温度,刷新了可控型稀磁半导体的居里温度记录.本文重点介绍 1)几种代表性的自旋和电荷掺杂机制分离的新型稀磁半导体的发现与研制;2)新型稀磁半导体的子自旋弛豫与高压物性结构的调控;3)大尺寸单晶生长、基于单晶的安德烈夫异质结研制以及自旋极化率的测量.通过新材料设计研制、综合物性研究、简单原型器件构建的“全链条”模式研究,开拓了自旋电荷分别掺杂的稀磁半导体材料研究领域,展现了这类新型稀磁半导体材料潜在的光明前景.
基金Supported by the National Natural Science Foundation and the Ministry of Science and Technology of Chinathe National Natural Science Foundation of China under Grant No U1530402+3 种基金the U.S. Department of Energy of Office of Science under Grant No DE-AC02-06CH11357the DOE-NNSA under Grant No DE-NA0001974the DOE-BES under Grant No DE-FG02-99ER45775the Instrumentation Funding of National Science Foundation
文摘The pressure effect on the crystalline structure of the I-II- V semiconductor Li（Zn,Mn）As ferromagnet is studied using in situ high-pressure x-ray diffraction and diamond anvil cell techniques. A phase transition starting at -11.6GPa is found. The space group of the high-pressure new phase is proposed as Pmca. Fitting with the Birch-Murnaghan equation of state, the bulk modulus B0 and its pressure derivative B0 of the ambient pressure structure with space group of F43m are B0 = 75.4 GPa and B0 = 4.3, respectively.
基金Project supported by the National Natural Science Foundation of ChinaProject of Ministry of Science and Technology of China
文摘The layered semiconductor BaFZnAs with the tetragonal ZrCuSiAs-type structure has been successfully synthesized.Both the in-situ high-pressure synchrotron x-ray diffraction and the high-pressure Raman scattering measurements demonstrate that the structure of BaFZnAs is stable under pressure up to 17.5 GPa at room temperature. The resistivity and the magnetic susceptibility data show that BaFZnAs is a non-magnetic semiconductor. BaFZnAs is recommended as a candidate of the host material of diluted magnetic semiconductor.
基金Project supported by the National Key R&D Program of China(Grant No.2017YFB0405703)the Ministry of Science and Technology of China(Grant Nos.2018YFA03057001 and 2015CB921000)the National Natural Science Foundation of China through the Research Projects(Grant Nos.11534016and 61504166)
文摘Chemical pressure induced by iso-valent doping has been widely employed to tune physical properties of materials. In this work, we report effects of chemical pressure by substitution of Sb or P into As on a recently discovered diluted magnetic semiconductor(Ba,K)(Zn,Mn)_2 As_2, which has the record of reliable Curie temperature of 230 K due to independent charge and spin doping. Sb and P are substituted into As-site to produce negative and positive chemical pressures, respectively.X-ray diffraction results demonstrate the successful chemical solution of dopants. Magnetic properties of both K-underdoped and K-optimal-doped samples are effectively tuned by Sb-and P-doping. The Hall effect measurements do not show decrease in carrier concentrations upon Sb-and P-doping. Impressively, magnetoresistance is significantly improved from7% to 27% by only 10% P-doping, successfully extending potential application of(Ba,K)(Zn,Mn)_2 As_2.
基金Project supported by the National Key R&D Program of China and the National Natural Science Foundation of China(Grant Nos.2018YFA0305700,2017YFA0302900,11974410,and 11534016)。
文摘A new compound with one-dimensional spin chains, Ba9Co3Se(15), was synthesized under high pressure and high temperature conditions and systematically characterized via structural, transport and magnetic measurements. Ba9Co3Se(15) crystallizes in a hexagonal structure with the space group P-6c2(No. 188) and lattice constants of a = b = 9.6765 ? and c = 18.9562 ?. The structure consists of trimeric face-sharing octahedral CoSe6 chains, which are arranged in a triangular lattice in the ab-plane and separated by Ba atoms. The distance of the nearest neighbor of CoSe6 chains is very large, given by the lattice constant a = 9.6765 ?. The Weiss temperature Tθ associated with the intra-chain coupling strength is about -346 K. However, no long-range magnetic order but a spin glass transition at ~ 3 K has been observed. Our results indicate that the spin glass behavior in Ba9Co3Se(15) mainly arises from the magnetic frustration due to the geometrically frustrated triangular lattice.
