γ-Al_(2)O_(3)/BaSnO_(3)异质结界面电子结构研究  

Electrical Structure of the Interface of γ-Al_(2)O_(3)/BaSnO_(3) Heterostructure

作　　者：侯冬雨 李志青[1] HOU Dongyu;LI Zhiqing(Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology,Department of Physics,Faculty of Science,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津市低维功能材料物理与制备技术重点实验室,天津大学物理系,天津300350

出　　处：《低温物理学报》2024年第2期131-142,共12页Low Temperature Physical Letters

基　　金：国家自然科学基金面上(批准号:12174282)资助的课题。

摘　　要：本文利用第一性原理计算研究了γ-Al_(2)O_(3)/BaSnO_(3)异质结中二维电子气(2DEG)的形成机制.计算结果表明当γ-Al_(2)O_(3)薄层的厚度超过临界厚度1.5 uc时,γ-Al_(2)O_(3)/BaSnO_(3)异质结界面处会有2DEG产生,此时2DEG的形成是由于界面处的极性不连续.在该异质结构中,导带电子分布在非简并的Sn 5s轨道上,具有较低的电子有效质量.当γ-Al_(2)O_(3)薄膜中存在氧空位时,极化电场消失,异质结界面处仍然有2DEG产生,且2DEG的产生不存在γ-Al_(2)O_(3)临界厚度的限制.此时界面处的2DEG源于异质结构中的氧空位.In this paper,we construct γ-Al_(2)O_(3)/BaSnO_(3) heterojunctions and their electronic structures are investigated using first-principles calculations.The results show that 2DEG is generated at the interface of the γ-Al_(2)O_(3)/BaSnO_(3) heterojunctions and when the thickness of the γ-Al_(2)O_(3) film exceeds the critical thickness by 1.5 uc.The formation of 2DEG is due to the polar discontinuity at the interface.The electrons at interface are distributed in the Sn 5s orbital,which has a low electron effective mass and is expected to have high mobility at room temperature.When there is an oxygen vacancy in the γ-Al_(2)O_(3) film,the polarization electric field disappears,and 2DEG still exists at the heterojunction interface,and there is no limitation of the critical thickness for the γ-Al_(2)O_(3) film.In this case,2DEG is formed due to the oxygen vacancy in the heterostructure.

关 键 词：锡酸钡 异质结 二维电子气 

分 类 号：O469[理学—凝聚态物理]