核回旋减弱,同位素丰富70 Ge/28 Si70 Ge 量子 Wells 量子 Wells 量子 Wells 量子 Wells 量子 Wells 量子 Wells 量子 Wells 量子 Wells 量子 Wells 量子 Wells
Oussama Moutanabbir1, Simone Assali1, Anis Attiaoui1
1Department of Engineering Physics, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville, Montréal, Québec, H3C 3A7, Canada.
Advanced materials (Deerfield Beach, Fla.)
|November 27, 2023
概括
无核旋转的 (Ge) 量子井使用同位素丰富材料进行了表层培养. 这大大减少了核自旋背景,提高了量子处理器中强大的洞自旋量子比特的前景.
科学领域:
- 量子计算是一种量子计算.
- 材料科学是一种材料科学.
- 凝聚物质物理学 凝聚物质物理学
背景情况:
- 由于较弱的超细相互作用,洞旋量子比特为量子处理器提供了潜在的潜力.
- 然而,洞量子位对核自旋浴非常敏感,因此需要无核自旋设计.
- 减少来自核旋转的脱凝是推动量子计算发展的关键.
研究的目的:
- 为了证明核无旋转的/- (SiGe) 量子井的表轴增长.
- 为了实现显著降低73Ge和29Si同位素的度.
- 研究同位素丰富对核自旋背景和量子比特连贯性的影响.
主要方法:
- 使用低压化学蒸气沉积的70Ge/SiGe量子井的长轴增长.
- 使用同位素净化70GeH4和28SiH4的纯度分别为>99.9%和>99.99%.
- 原子探头断层扫描 (APT) 用于精确的同位素纯度分析和核自旋度的确定.
主要成果:
- 成功生长了70Ge/SiGe量子井,其73Ge和29Si度低于0.01%.
- 实现了核旋转之间的平均距离为3-4纳米,比自然的Ge/SiGe大一个数量级.
- 证明了核自旋背景的实质性减少,这对于量子比特连贯性至关重要.
结论:
- 以同位素丰富的70Ge/28SiGe异构结构使得洞量子位能够创建无核自旋环境.
- 这种方法显著抑制了非连贯性,为更强大的量子处理器铺平了道路.
- 开发的生长和表征方法对于未来的量子技术至关重要.
相关概念视频
01:03Atomic Nuclei: Nuclear Spin State Overview
964
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of...
964
01:14Atomic Nuclei: Nuclear Spin State Population Distribution
987
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
987
01:08Atomic Nuclei: Nuclear Spin
1.9K
All atomic particles possess an intrinsic angular momentum, or 'spin'. Electrons, protons, and neutrons each have a spin value of ½, although protons and neutrons in nuclei may have higher half-integer spins owing to energetic factors.
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not...
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not...
1.9K
01:23Atomic Nuclei: Nuclear Relaxation Processes
657
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
657
01:07Nuclear Overhauser Enhancement (NOE)
701
Irradiation of a spin-active nucleus causes an increase or decrease in the signal intensity of neighboring nuclei that are not necessarily chemically bonded or involved in J-coupling. This phenomenon, called the Nuclear Overhauser Enhancement (NOE), results from through-space interactions between the nuclear spins. The NOE effect decreases with increasing internuclear distance and is generally not observed beyond 4 angstroms. In NOE, dipole-dipole interactions between neighboring...
701
01:05Atomic Nuclei: Magnetic Resonance
663
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
663