Motivated by the recent successful synthesis of the layered platinum mineral jacutingaite (Pt₂HgSe₃), we have studied the optoelectronic, mechanical, and thermoelectric properties of graphene hetero-multilayer on Pt₂HgSe₃ monolayer (PHS) heterostructures (LG/PHS) by using first-principles calculations. PHS is a topological insulator with a band gap of about 160 meV with fully relativistic calculations; when graphene layers are stacked on PHS, a narrow band gap of ∼10–15 meV opens. In the presence of gate-voltage and out-of plane strain, i.e. pressure, the electronic properties are modified; the Dirac-cone of graphene can be shifted upwards (downward) to a lower (higher) binding energy. The absorption spectrum shows two peaks, which are located around 216 nm (5.74 eV) and protracted to 490 nm (2.53 eV), indicating that PHS could absorb more visible light. Increasing the number of graphene layers on PHS has a positive impact on the UV-vis light absorption and gives a clear red-shift with enhanced absorption intensity. To investigate the electronic performance of the heterostructure, the electrical conductance and thermopower of a device composed of graphene layers and PHS is examined by a combination of DFT and Green function formalism. The number of graphene layers can significantly tune the thermopower and electrical conductance. This analysis reveals that the heterostructures not only significantly affect the electronic properties, but they can also be used as an efficient way to modulate the optic and thermoelectric properties.

中文翻译：

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层状铂金矿物钠铝矾石（Pt2HgSe3）上的石墨烯异质多层：具有新颖光电和热电性能的范德华异质结构

由于最近成功合成了层状铂矿物Jacutingaite（Pt ₂ HgSe ₃），我们研究了Pt ₂ HgSe ₃单层（PHS）异质结构（LG / PHS）上的石墨烯异质多层的光电，机械和热电性能通过使用第一性原理计算。PHS是一种拓扑绝缘体，其带隙约为160 meV，经过完全相对论计算；当石墨烯层堆叠在PHS上时，会出现〜10–15 meV的窄带隙。在存在栅极电压和面外应变的情况下，即压力，电子性能被修改；石墨烯的狄拉克锥可以向上（向下）移动到较低（较高）的结合能。吸收光谱显示两个峰值，位于216 nm（5.74 eV）附近，并延长至490 nm（2.53 eV），表明PHS可以吸收更多可见光。在PHS上增加石墨烯层的数量会对UV-vis光吸收产生积极影响，并在吸收强度增强的情况下产生明显的红移。为了研究异质结构的电子性能，结合DFT和Green函数形式，研究了由石墨烯层和PHS组成的器件的电导率和热功率。石墨烯层的数量可以显着调整热功率和电导率。