Electrical Conductivity Measurement of -Boron under High Temperature and High Pressure
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摘要: 硼在高压下具有复杂的结构和多样的物理性质,对其结构和性质的深入研究具有很重要的意义,一直引起理论和实验研究领域的关注。高压下进行电学性质测量是获得物质物理性质的有效手段,利用集成在金刚石对顶砧上的微电路,在高压下和两个不同温度范围内对相硼进行了电导率测量,分析了导电机制随压力的变化规律。在0~28.1 GPa范围内,相硼的电导率随着压力的增大是逐渐增大的,卸压后样品的电导率不能回到最初的状态,是一个不可逆的变化过程;由室温到423 K的范围内,硼的电导率随着温度的不断增加有明显的上升趋势,并且随着压力的升高,电导率变化逐渐加快。此外,对样品在14.5 GPa和18.6 GPa压力下,用溅射到金刚石对顶砧上的氧化铝薄膜做绝热层,对样品进行了激光加热实验,最高温度达到2 224 K,电导率随着温度的上升而增大,结果显示,相硼的电学特征仍然属于半导体的特征范围内。Abstract: Boron possesses very complex structures and various physical characteristics under high pressure, which always attracts much attention in the field of theory and experiment. In situ electrical conductivity measurement under variable pressure and temperature conditions is a very important research into exploring conductive property of substance. Electrical conductivity of -B was measured with metallic microcircuit fabricated on the diamond anvil cell (DAC), and the conductive physical mechanism of -boron at high pressure and high temperature was analyzed. When sample was not heated, electrical conductivity of boron was rising with increasing pressure to 28 GPa; furthermore, we found that it almost recovers original state upon decompression. When temperature is changed from room temperature to 423 K, electrical conductivity begins to rise with increasing temperature, and the change rate becomes gradually high and the change trend of electrical conductivity is similar to that under different pressures in the same temperature range. Subsequently, laser-heating was performed on -B with designed DAC, Al2O3 thin film was deposited on the diamond anvil and used as heat resistant and electrical insulating layer. Electrical conductivity was separately measured at 14.5 GPa and 18.6 GPa. The highest temperature reached is 2 224 K. -boron is confirmed semiconductor property based on electrical conductivity increasing with elevated temperature.
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Key words:
- high temperature and high pressure /
- -boron /
- electrical conductivity
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Brazhkin V V, Lyapin A G, Hemley R J. Harder than Diamond: Dreams and Reality [J]. Philos Mag A, 2002, 82: 231. Nagamatsu J, Nakagawa N, Muranaka T, et al. Superconductivity at 39 K in Magnesium Diboride [J]. Nature(London), 2001, 410: 63. Fujimori M, Nakata T, Nakayama T. Peculiar Covalent Bonds in a-Rhombohedral Boron [J]. Phys Rev Lett, 1999, 82: 4452-4455. Young D A. Phase Diagrams of the Elements [M]. Berkeley, CA: Univ of Califormia Press, 1991: 88. Emin D. Icosahedral Boron-Rich Solids [J]. Phys Today, 1987, 40: 1-55. Shiraiphys K. High-Pressure Properties of Icosahedron-Based Solid Borons [J]. Stat Sol(b), 2004, 241: 3161-3167. Ma Y Z, Prewitt C T, Zou G T, et al. High-Pressure High-Temperature X-Ray Diffraction of -Boron to 30 GPa [J]. Phys Rev B, 2003, 67: 174116. Eremets M I, Struzhkin V V, Mao H K, et al. Superconductivity in Boron [J]. Science, 2001, 293: 272. Segall D E, Arias T A. Ab Initio Approach for High-Pressure Systems with Application to High-Pressure Phases of Boron: Perturbative Momentum-Space Potentials [J]. Phys Rev B, 2003, 67: 064105. Haussermann U, Simak S I, Ahuja R, et al. Metal-Nonmetal Transition in the Boron Group Elements [J]. Phys Rev Lett, 2003, 90: 065701. The Ultrahigh-Pressure Diamond Cell: Design Applications for Electrical Measurements of Mineral Samples at 1. 2 Mbar [J]. Canegie Inst Washington Yearb, 1976, 75: 824. Grzybowski T A, Ruoff A L. Band-Overlap Metallization of BaTe [J]. Phys Rev Lett, 1984, 53: 489. Eremets M I, Shimizu K, Kobayashi T C, et al. Metallic CsI at Pressures of up to 22 Gigapascals [J]. Science, 1998, 281: 1333. Weir S T, Akella J, Aracne-Ruddle C, et al. Epitaxial Diamond Encapsulation of Metal Microprobes for High Pressure Experiments [J]. Appl Phys Lett, 2000, 77: 3400. Han Y H, Gao C X, Ma Y Z. Integrated Microcircuit on a Diamond Anvil for High-Pressure Electrical Resistivity Measurement [J]. Appl Phys Lett, 2005, 86: 064104. Hearne G, Bibik A, Zhao J. Equation of State and Pressure Induced Amorphization of -Boron from X-Ray Measurements up to 100 GPa [J]. J Phys Condens Mater, 2002, 14: 11531-11535. Sanz D N, Loubeyre P, Mezouar M. Equation of State and Pressure Induced Amorphization of -Boron from X-Ray Measurements up to 100 GPa [J]. Phys Rev Lett, 2002, 89: 245501. Masago A, Shirai K, Katayama-Yoshida H. Crystal Stability of -and -Boron [J]. Phys Rev B, 2006, 73: 104102. Sham W C, Hukson D E, Danielson G C. Eelectrical Properties of Boron Single Crystals [J]. Phys Rev, 1956, 107: 419.
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