Structural, Electronic, and Transport Properties of Hybrid SrTiO3-Graphene and Carbon Nanoribbon Interfaces
Structural, Electronic, and Transport Properties of Hybrid SrTiO3-Graphene and Carbon Nanoribbon Interfaces
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DOI：
10.1021/acs.chemmater.7b02253
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发表时间：
2017-09-12
影响因子：
8.6
通讯作者：
Parker, Stephen C.
中科院分区：
文献类型：
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作者：
Baran, Jakub D.;Eames, Christopher;Parker, Stephen C.
由不同功能结构单元组成的杂化材料提供了独立调节材料的热学和电学性质的可能性。通过量子力学计算，我们研究了石墨烯和氢端碳纳米带(CNR)放置在SrTiO_3(001)表面(STO)时的电子输运和热电输运性质的变化。我们预测，通过将石墨烯/碳纳米管偶联到STO的不同表面端基上，可以获得p型和n型复合材料。结果表明，在SRO封端的STO上，石墨烯和CNR的电子性质发生了显著的变化，但在与二氧化钛封端的STO相互作用时保持不变，并且由于CNR的准一维性质，CNR在费米能级附近具有明显的电子态，导致计算的Seebeck系数比原始石墨烯的大得多。此外，我们的计算表明，在Ti-02-SrTiO_3/CNR体系中，CNR和STO之间存在良好的电子能级排列，其中CNR的最高占据分子轨道位于STO禁带的中间，类似于衬底的n型掺杂。我们的结果为指导未来混合热电材料的工程设计提供了设计原则，更广泛地说，包括氧化物和石墨组件的纳米电子材料。
Hybrid materials composed of different functional structural units offer the possibility of tuning both the thermal and electronic properties of a material independently. Using quantum mechanical calculations, we investigate the change in the electronic and thermoelectric transport properties of graphene and hydrogen-terminated carbon nanoribbons (CNRs) when these are placed on the SrTiO3 (001) surface (STO). We predict that both p-type and n-type composite materials can be achieved by coupling graphene/CNR to different surface terminations of STO. We show that the electronic properties of graphene and CNR are significantly altered on SrO-terminated STO but are preserved upon interaction with TiO2-terminated STO and that CNRs possess distinct electronic states around the Fermi level because of their quasi-one-dimensional nature, leading to a calculated Seebeck coefficient much higher than that of a pristine graphene sheet. Moreover, our calculations reveal that in the Ti-02-SrTiO3/CNR system there is a favorable electronic level alignment between the CNR and STO, where the highest occupied molecular orbital of the CNR is positioned in the middle of the STO band gap, resembling n-type doping of the substrate. Our results offer design principles for guiding the engineering of future hybrid thermoelectric materials and, more generally, nanoelectronic materials comprising oxide and graphitic components.