华东师范大学学报(自然科学版) ›› 2017, Vol. 2017 ›› Issue (2): 97-106.doi: 10.3969/j.issn.1000-5641.2017.02.013

• 物理学与电子学 • 上一篇    下一篇

可用作量子比特的一种负价态VSiON缺陷中心

沈宇皓1, 唐政1, 彭伟2   

  1. 1. 华东师范大学 极化材料与器件重点实验室, 上海 200241;
    2. 华东师范大学 信息化办公室, 上海 200062
  • 收稿日期:2016-03-16 出版日期:2017-03-25 发布日期:2017-03-23
  • 作者简介:沈宇皓,男,硕士研究生,研究方向为半导体材料物理.E-mail:slyhb2126@163.com
  • 基金资助:

    国家杰出青年科学基金(61425004)

A negatively charged VSiON center for implementation as qubit

SHEN Yu-hao1, TANG Zheng1, PENG Wei2   

  1. 1. Key Laboratory of Polar Materials and Devices, East China Normal University, Shanghai 200241, China;
    2. Information Technology Services Center, East China Normal University, Shanghai 200062, China
  • Received:2016-03-16 Online:2017-03-25 Published:2017-03-23

摘要:

γ相Si3N4是一种超硬氮基化合陶瓷材料,在其尖晶石结构中硅原子分别占据四面体于八面体配位格点.基于第一性原理计算,研究了这种材料之中一种氧空位复合体VSiON缺陷中心的不同价态下自旋极化的电子结构以及能量稳定性,其中该缺陷中心由四面体配位的硅空位复合紧邻替位氧原子而成.发现负一价态的该缺陷中心VSiON-1在p型主体材料中是较为稳定的存在,并满足净自旋S=1的基态三重态,以及低激发能量的自旋守恒跃迁.通过平均场近似,将其在绝对零度下的自旋相干寿命估计为0.4 s,室温下可达毫秒量级.因此理论上表明了VSiON-1缺陷中心是可用作量子比特的相干操控的潜在候选者.

关键词: 第一性原理计算, 自旋极化电子结构, 自旋相干时间, 色心的量子比特操控

Abstract:

γ-Si3N4 is a nitrogen-based ultra-hard ceramic with Si atoms occupying both tetrahedral and octahedral sites in a spinel structure. Based on first-principles calculations, we investigate spin-polarized electronic structures and energetic stabilities of oxygenvacancy complex center (VSiON) consisting of a substituted oxygen atom and an adjacent tetrahedrally coordinated silicon vacancy in spinel silicon nitride (γ-Si3N4) with different charge states. We find that the negatively charged VSiON-1 center is stable in the p-type γ-Si3N4 and the defect center possesses an S=1 triplet ground state and a spin-conserved excited state with low excitation energy. By using a mean-field approximation, we estimate that the spin coherence time of VSiON is 0.4 s at T=0 K, which indicates that the VSiON-1 center is a promising candidate for spin coherent manipulation and qubit operation.

Key words: first-principles calculations, spin-polarized electronic structures, spin coherent time, qubit operation of color centers

中图分类号: