Pressure‑induced structural transition and metallization in MnSe2
Pressure‑induced structural transition and metallization in MnSe2
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压力诱导的 MnSe2 结构转变和金属化
DOI：
10.1007/s00269-020-01111-9
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发表时间：
2020
影响因子：
1.4
通讯作者：
Maoshuang Song
中科院分区：
文献类型：
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作者：
Baoyun Wang;Xiaoning Wang;Simeng Wang;Dayong Tan;Wansheng Xiao;Wen Liang;Maoshuang Song
采用同步辐射角色散X射线衍射仪(ADXRD)和金刚石-压腔红外反射光谱仪研究了二硒化锰MnSe_2的高压行为。激光热处理证实，具有黄铁矿结构的MnSe_2在~ 为12.5 GPa时发生了向无序中间相的转变，基态为毒砂结构。黄铁矿到毒砂的相变与晶胞体积的大幅崩塌(∆V~ 19%)和锰离子(Mn2+)从高自旋态到低自旋态的电子跃迁相耦合。在压力导数K‘= 4不变的情况下，用二阶Birch-Murnaghan状态方程对压力-体积数据进行拟合，得到黄铁矿和毒砂相的等温体积模量值分别为K0= 56.1(9) 和K0=GpA 93.1(4)。测量的MnSe2的红外反射率(RSD)表明，在13~20 Gpa的压力下，MnSe2的红外反射率急剧增加，但在进一步压缩下对压力不敏感，这意味着压力诱导的绝缘体向金属状态的转变。
The high-pressure behavior of manganese diselenide MnSe2was investigated by synchrotron angle-dispersive X-ray diffraction (ADXRD) and infrared reflection spectroscopy equipped with a diamond-anvil cell. It was found that MnSe2with a pyrite-type structure undergoes a transformation into a disordered intermediate phase at ~ 12.5 GPa, with a ground state composed of an arsenopyrite-type structure, as confirmed by laser-heating treatment. The pyrite to arsenopyrite phase transition was found to be coupled to a large collapse in the unit-cell volume (∆V~ 19%) and an electronic transition from a high-spin to low-spin state for manganese cations (Mn2+). With a fixed value for the pressure derivation of the bulk modulusK'= 4, fitting of the pressure–volume data to a second-order Birch–Murnaghan equation of state yielded isothermal bulk modulus values ofK0= 56.1(9) GPa andK0= 93.1(4) GPa for the pyrite-type and arsenopyrite-type phases, respectively. The measured infrared reflectivity (Rsd) for MnSe2showed a drastic increase at pressures between 13 and 20 GPa, but became insensitive to pressure under further compression, implying a pressure-induced transition from an insulator to metallic state.