Unique Conduction Band Minimum of Semiconductors Possessing a Zincblende-Type Framework
Unique Conduction Band Minimum of Semiconductors Possessing a Zincblende-Type Framework
复制标题
DOI：
10.1021/acs.inorgchem.2c00884
复制
发表时间：
2022-06-28
影响因子：
4.6
通讯作者：
Hosono, Hideo
中科院分区：
文献类型：
--
作者：
Mizoguchi, Hiroshi;Park, Sang-Won;Hosono, Hideo
四面体半导体如Si采用金刚石型晶体结构，其具有由晶体空间中的开放腔引起的低堆积密度。以LiAlGe为例，我们提出了一种锌合金型框架作为具有电活性腔的半导体平台。LiAlGe采用包括有序金刚石型亚晶格（闪锌矿型）（AlGe）的半赫斯勒型晶体结构，并且是具有类似于0.1eV的带隙的间接半导体。在真实的空间中，导带底（CBM）唯一地位于四个阳离子（Al-4）包围的腔空间中。位于费米能级附近的键离子性和阳离子（Al）p轨道是CBM在腔空间中漂浮的必要条件。密度泛函理论计算表明，在近似8 GPa的压力下，半导体转化为半金属氧化物，这是伴随着由于电子从价带最大值转移到腔空间的带隙崩溃。在很小的临界压力下形成的LiAlGe的高压晶格是由具有深轨道能级的固有晶体学空穴的存在而产生的。这一发现表明，四面体半导体中的电活性腔空间可能被利用，四面体半导体广泛用于现代电子器件。
Tetrahedral semiconductors such as Si adopt a diamond-type crystal structure with low packing density arising from open cavities in the crystallographic space. By taking LiAlGe as an example, we propose a zincblende-type framework as a platform for semiconductors possessing electroactive cavities. LiAlGe adopts a half-Heusler-type crystal structure including an ordered diamond-type sublattice (zincblende-type) (AlGe) and is an indirect semiconductor with a band gap of similar to 0.1 eV. The conduction band minimum (CBM) is uniquely located at the cavity space surrounded by four cations (Al-4) in real space. The bond ionicity and cation (Al) p orbitals located around the Fermi energy are requisite for the CBM to float in the cavity space. DFT calculations indicate the conversion of the semiconductor to a semimetallic electride under a pressure of similar to 8 GPa, which is accompanied by band gap collapse due to electron transfer from valence band maximum to the cavity space. The high-pressure electride of LiAlGe formed under a very small critical pressure is derived from the presence of inherent crystallographic cavities having deep orbital levels energetically. This finding suggests the possible utilization of electroactive cavity spaces in tetrahedral semiconductors, which are widely used in modern electronic devices.