Thoretical Study on Electronic Structures and Pressure-Induced Composite Phase Transitions of Solid Oxygen

从波段结构计算使用充分潜力（FP）-用于氧化物分子阶段的LMTS方法我们已经获得了以下重要结果：1。在环境压力下，最稳定的状态是AF状态。压力诱导的胰岛素-金属过渡发生在波段上，因为它关闭了间接的能量差距。At the transition volume V-D2M-D2=25.98铜-D13-D1， the magnetic moment still remains in each molecule.3。With farther decreasing the volume the magnetic moment disappears and the paramagnetic metallic phase is realized at V-D2M-D2=11.36-phase at 116 GPa（V型D2 M型D2=11.36型）。由于晶体结构我们选择了β-Po型，因为它是一个真正的单体结构，首先在高p以下 ... More 其他VI-B元素的风险。β-Po型结构是rhombohedral和sc、bcc和fcc结构，以满足β-Po型结构的c/a的特殊价值。我们找到了具有相同体积的总能量-Po oxygen高于其分子特性（monoclinic）相位。因此，我们强烈地认为，从我们计算的所有结果中得出结论，即超磁性金属状态在高压下的分子固体氧化物高于100 GPa，我们也在Allen-Dynes formalism的框架中研究了压力诱导的β-Po Se （60 GPa < P < 150 GPa）和bcc Se （150 GPa < P）的超导电性。在bcc阶段的超传导过渡温度T-D2c-D2增加了与decreasing pressure的关系，并且T-D2c-D2到达超过10 K的过渡从bcc到β-Po。The origin of this remarkable increase of T-D2c-D2 is mainly attributed to phonon anomaly in the middle of the-N line。在β-Po phase上，在另一边，T-Po D2几乎是压力独立的（~ 5 K），在T-Po D2的过渡中有一个大跳跃。Less（低）

From band structure calculations using full-potential (FP)-LMTO method for molecular phases of oxygen we have obtained the following important results:1. At ambient pressure the most stable state is the AF state.2. Pressure-induced insulator-metal transition occurs by band overlapping which closes the indirect energy gap. At the transition volume VィイD2MィエD2=25.98 ÅィイD13ィエD1, the magnetic moment still remains in each molecule.3. With farther decreasing the volume the magnetic moment disappears and the paramagnetic metallic phase is realized at VィイD2MィエD2=11.36 ÅィイD13ィエD1 which corresponds to the ζ-phase at 116 GPa.In order to see a possibility that the observed metallization is realized in a monatomic phase of solid oxygen we have performed band calculations of monatomic phases for the volume corresponding to that of the ζ-phase at 116 GPa(VィイD2MィエD2=11.36 ÅィイD13ィエD1). As the crystal structure we have chosen the β-Po type because it is the monatomic structure realized first under high p … More ressures in other VI-b elements. The β-Po type structure is rhombohedral and the sc, bcc and fcc structures are realized for special values of c/a of β-Po type structure. We have found that the total energy of β-Po oxygen is higher than that of the molecular ζ(monoclinic) phase obtained for the same volume. Therefore, judging from all the results of our calculations it is strongly suggested that a paramagnetic metallic state is realized in molecular solid oxygen under high pressures higher than about 100 GPa.We investigated also pressure-induced superconductivity of β-Po Se (60 Gpa < P < 150 Gpa) and of bcc Se (150 Gpa < P) in the frame work of Allen-Dynes formalism. In the bcc phase the superconducting transition temperature TィイD2cィエD2 increases considerably with decreasing pressure, and TィイD2cィエD2 reaches more than 10 K at the transition from bcc to β-Po. The origin of this remarkable increase of TィイD2cィエD2 is mainly attributed to phonon anomaly in the middle of the ГN line. In β-Po phase, on the other hand, TィイD2cィエD2 is almost pressure independent (〜5K) and there is a large jump in TィイD2cィエD2 at the transition from β-Po to bcc. Less