Unexpected High-Pressure Phase of GeTe with an Origin of Low Ionicity and Electron Delocalization,The Journal of Physical Chemistry C

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Unexpected High-Pressure Phase of GeTe with an Origin of Low Ionicity and Electron Delocalization
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2018-06-26 , DOI: 10.1021/acs.jpcc.8b03984
Hulei Yu ₁ , Yue Chen ₁

Affiliation

First-principles evolutionary searches have been performed to systematically explore the high-pressure phases of germanium telluride. Two new phases are found to be both energetically and dynamically stable under moderate pressures. A Pnma orthorhombic phase with an uncommon “boat” conformation and a P4/nmm tetragonal phase are found to become stable at ∼15 and ∼37 GPa, respectively. The long-believed high-pressure B2 phase, however, is found to be energetically unfavorable comparing to the P4/nmm phase. Our calculations of the electronic structures show that Pnma-boat GeTe and P4/nmm GeTe exhibit semimetallic and metallic behaviors, respectively. On the basis of the electron–phonon coupling calculations, P4/nmm GeTe is shown to have a superconducting transition at low temperatures, resulting from its sudden decrease of ionicity and the more delocalized lone-pair electrons. The discovery of these new GeTe phases further enriches our knowledge of the high-pressure behaviors of the IV–VI compounds.

中文翻译：

低离子化和电子离域的起源的意想不到的GeTe高压相

进行了第一性原理的进化搜索以系统地探索碲化锗的高压相。发现在适度的压力下能量稳定和动态稳定的两个新阶段。发现具有罕见“船形”构象的Pnma正交相和P 4 / nmm的四方相分别在约15 GPa和约37 GPa时变得稳定。然而，与P 4 / nmm相相比，人们认为长期以来认为的高压B2相在能量上不利。我们对电子结构的计算表明，Pnma晶格GeTe和P 4 / nmmGeTe分别表现出半金属和金属行为。根据电子-声子耦合计算，显示P 4 / nmm GeTe在低温下具有超导转变，这是由于其离子性突然降低和离域的孤对电子更加突然所致。这些新的GeTe相的发现进一步丰富了我们对IV-VI化合物高压行为的了解。

更新日期：2018-06-27

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