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各位大虾帮忙翻译一下，急！谢谢！ It is interesting to consider the phase diagram that results if we exclude the Ta5N6 phase （e.g., if it is prevented from forming due to particular experimental conditions）. The result is shown in Fig. 4（d）. In this case, in addition to the Ta2N and Ta3N5 phases, which are now favorable over a larger region, the Ta4N5 structure appears in a relatively wide range of （ μN,μTa）phase space and, in addition, a structure containing N vacancies in a rocksalt lattice is seen （rs-Ta4N3）. It can be noticed that when sweeping from right to left in the phase diagram and going from high μN, low μTa to more low μN, high μTa conditions, the Ta to N ratio increases;namely, it changes from 0.6 （Ta3N5） to 0.8 （Ta4N5） to 1.33 （rs-Ta4N3） to 2.0 （Ta2N）; that is, the phases change from so-called “higher nitrides” to “lower nitrides.” This is similar to the trend found in Ref. 2 when heating the Ta3N5 phase under UHV as described in the Introduction, which causes desorption and loss of N atoms as N2, resulting in progressively more Ta-rich materials. In Figs. 4（c）and 4（d）, the scale of the N chemical potential is correlated with the N2 pressure for two selected temperatures [cf. Eq. (2)]. At 600 K, it can be seen from Fig. 4(c) that for pressure ranges used in industry and laboratories—i.e., from ultrahigh vacuum to 100 atm (10−15~100 atm or 0.65×10−12–0.65×105 Torr）, which correspond to mN in the range of ,−0.4 to ,−1.4 eV, the Ta5N6 phase is the most stable. This is also the case at 1000 K even though the corresponding range of μN is shifted and considerably extended（~-0.8 to ~−2.4 eV）. Considering Fig. 4（d）, however,which contains the metastable N-vacancy structure（rs-Ta4N3） and Ta4N5 phase, it can be seen that at 600 K,Ta4N5 is favored, while at 1000 K, depending on the pressure,either Ta4N5, rs-Ta4N3, or even Ta2N may be favored.Thus, through variation of the temperature and pressure, different structures become energetically favored, and in general, structures with higher N contents are predicted for higher N2 pressures, while for a given pressure, higher temperatures are predicted to give rise to more N-deficient structures.This is in qualitative agreement with the experimental results. In summary, through highly precise total energy FLAPW calculations we studied the relative stability and associated electronic properties of stable and metastable structures of the Ta-N system. In all cases, the calculated equilibrium volume is in excellent agreement with experiment. We find that there are three stable phases—namely, Ta2N, Ta5N6, and Ta3N5; the rest are metastable. The electronic properties range from strongly metallic （Ta2N） to more resistive（Ta5N6） and finally to insulating （Ta3N5）. The very close energies calculated for the various structures investigated for certain regions of the phase diagram suggest that kinetic effects（due, e.g., to diffusion barriers for atomic rearrangement or epitaxial stabilization effects） will play an important role for this complex system and that the chemical and phase compositions of deposited films will depend critically on the growth conditions. This is in accordance with, and helps explain, the wide range of different structures observed experimentally. |
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11楼2011-03-03 18:40:28
寂寞倾城(金币+5, 翻译EPI+1): 2011-03-03 15:11:17
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It is interesting to consider the phase diagram that results if we exclude the Ta5N6 phase （e.g., if it is prevented from forming due to particular experimental conditions）. The result is shown in Fig. 4（d）. In this case, in addition to the Ta2N and Ta3N5 phases, which are now favorable over a larger region, the Ta4N5 structure appears in a relatively wide range of （ μN,μTa）phase space and, in addition, a structure containing N vacancies in a rocksalt lattice is seen （rs-Ta4N3）. It can be noticed that when sweeping from right to left in the phase diagram and going from high μN, low μTa to more low μN, high μTa conditions, the Ta to N ratio increases;namely, it changes from 0.6 （Ta3N5） to 0.8 （Ta4N5）to 1.33 （rs-Ta4N3） to 2.0 （Ta2N）; that is, the phases change from so-called “higher nitrides” to “lower nitrides.” This is similar to the trend found in Ref. 2 when heating the Ta3N5 phase under UHV as described in the Introduction, which causes desorption and loss of N atoms as N2, resulting in progressively more Ta-rich materials. 如果我们排除Ta5N6阶段（例如，如果由于特定的实验条件未能形成），考虑得到的相图将很有趣。结果如图4（d）所示。在这种情况下，除了目前已在更大区域有利的Ta2N和Ta3N5阶段，Ta4N5结构出现在一个比较宽的范围（μN，μTa）相空间，此外，可以看到一个包含了N空位是岩盐格结构（rs - Ta4N3）。可以注意到，当由右至左清扫相图，由高μN、低μTa，到更低μN、高μTa条件， Ta /N比增加，从0.6（Ta3N5）至0.8 （Ta4N5）至1.33（rs - Ta4N3）至2.0（Ta2N）改变，也就是说，相变是从所谓的“高氮化物”到“低氮化物”，变化趋势与在参考文献2发现的类似，如引言中所述，特高压下加热的Ta3N5相，这将导致脱附和氮原子以N2形式损耗，造成富Ta材料的逐步形成。 |
2楼2011-03-03 14:57:01
3楼2011-03-03 15:17:54
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