AG真人唯一平台《材料科学论坛》学术报告

报告时间：2023年9月22日上午10:00

报告人：韩拯教授（山西大学）

报告地点：清华—富士康纳米中心四楼报告厅

邀请人：刘锴老师

报告题目：基于长程电荷序量子效应的新原理半导体器件探索

报告简介：

Over the past half-century, exciton insulators have been observed in various experimental systems, predominantly through indirect spectroscopic studies. However, there is a notable lack of studies on the electrical transport and gate-tuning of this correlated insulator. The main reason for this limitation is the difficulty in controlling the strength of electron correlations in semi-metallic systems (or narrow bandgap semiconductors) near charge neutrality.

In this talk, we show that by bringing Bernal-stacked bilayer graphene (BLG) into contact with a few-layered insulator CrOCl, the resulted vertical heterostructures can give rise to an extraordinarily robust ground state of insulator at the charge neutrality [1]. This emerged band-gap is of quantum origin, and can be controlled by in-plane electric fields, vertical electric fields, temperature, and carrier density.

Based on this correlated insulating state, both N-type and P-type transistors are achieved. Further, CMOS-like semiconducting BLG logic inverter with a gain of approximately 1.2 (yet to be improved) at a temperature of 1.5 K at an input voltage of 0.2 V can be realized. This could be a crucial step forward for future carbon computing.

Unlike the conventional approaches based on intrinsic band gaps and doping principles in silicon-based semiconductors and two-dimensional semiconductors, the route of quantum-origin correlated gapped state employed in this study breaks new ground. It constructs long-range charge order at the interface by utilizing interface coupling and then leverages the interface states to influence electronic correlations in graphene. This coupling mechanism represents a universal control method and holds the potential for discovering intriguing physical phenomena in a broader range of two-dimensional electron systems [2].

[1] K. N. Yang, X. Gao, Y. Wang, T. Zhang, et al, Nat. Commun., 14, 2136 (2023).

[2] X. Lu, et al., Nat. Commun., 14, 5550 (2023).

报告人简介：

山西大学韩拯教授在新原理低维量子器件等方面取得系列进展：演示了本征二维磁性半导体自旋场效应管（Nat. Nanotechnol., 13, 554, 2018）；发现了门电压可调的二维巨各向异性电阻效应（Nat. Nanotechnol., 10, 2302, 2019）；制备的达到物理极限的单原子层亚纳米鳍片宽度FinFET 鳍栅晶体管（Nat. Commun., 11, 1205, 2020）入选《半导体学报》“中国半导体十大进展”；揭示了双重对齐莫尔超晶格中弱相互作用下的关联绝缘态（Nat. Commun., 12, 7196, 2021）；发展了一种界面电荷序调控二维电子气关联效应的新方法，实现了极具鲁棒性量子霍尔态，液氮温度获得量子化边界导电态只需要0.35 T磁场，为目前的世界记录（Nat. Nanotechnol., 17, 1272, 2022）。韩拯教授先后入选国家级海外青年人才计划、国家级特殊人才支持计划；曾获“山西省五四青年奖章”、“山西省五一劳动奖章”、“MIT科技评论中国区35岁以下创新35人”等荣誉。