JUSTC

Freestanding oxide membranes: synthesis, tunable physical properties, and functional devices

Ao Wang, Jinfeng Zhang, Lingfei Wang

2024, 54(7): 0701. doi: 10.52396/JUSTC-2023-0103

Article Views:(250) HTML (250) Full article PDF(605)

Abstract:
The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping, which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide systems. Recently, however, the development of freestanding oxide membranes has provided a plausible solution to these substrate limitations. Single-crystalline functional oxide films can be released from their substrates without incurring significant damage and can subsequently be transferred to any substrate of choice. This paper discusses recent advancements in the fabrication, adjustable physical properties, and various applications of freestanding oxide perovskite films. First, we present the primary strategies employed for the synthesis and transfer of these freestanding perovskite thin films. Second, we explore the main functionalities observed in freestanding perovskite oxide thin films, with special attention tothe tunable functionalities and physical properties of these freestanding perovskite membranes under varying strain states. Next, we encapsulate three representative devices based on freestanding oxide films. Overall, this review highlights the potential of freestanding oxide films for the study of novel functionalities and flexible electronics. The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping, which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide systems. Recently, however, the development of freestanding oxide membranes has provided a plausible solution to these substrate limitations. Single-crystalline functional oxide films can be released from their substrates without incurring significant damage and can subsequently be transferred to any substrate of choice. This paper discusses recent advancements in the fabrication, adjustable physical properties, and various applications of freestanding oxide perovskite films. First, we present the primary strategies employed for the synthesis and transfer of these freestanding perovskite thin films. Second, we explore the main functionalities observed in freestanding perovskite oxide thin films, with special attention tothe tunable functionalities and physical properties of these freestanding perovskite membranes under varying strain states. Next, we encapsulate three representative devices based on freestanding oxide films. Overall, this review highlights the potential of freestanding oxide films for the study of novel functionalities and flexible electronics.

Balancing the minimum error rate and minimum copy consumption in quantum state discrimination

Boxuan Tian, Zhibo Hou, Guo-Yong Xiang, Chuan-Feng Li, Guang-Can Guo

2024, 54(7): 0704. doi: 10.52396/JUSTC-2023-0155

Article Views:(137) HTML (137) Full article PDF(432)

Abstract:
Extracting more information and saving quantum resources are two main aims for quantum measurements. However, the optimization of strategies for these two objectives varies when discriminating between quantum states

\begin{document}$ |\psi_0\rangle$\end{document}

and

\begin{document}$|\psi_1\rangle $\end{document}

through multiple measurements. In this study, we introduce a novel state discrimination model that reveals the intricate relationship between the average error rate and average copy consumption. By integrating these two crucial metrics and minimizing their weighted sum for any given weight value, our research underscores the infeasibility of simultaneously minimizing these metrics through local measurements with one-way communication. Our findings present a compelling trade-off curve, highlighting the advantages of achieving a balance between error rate and copy consumption in quantum discrimination tasks, offering valuable insights into the optimization of quantum resources while ensuring the accuracy of quantum state discrimination. Extracting more information and saving quantum resources are two main aims for quantum measurements. However, the optimization of strategies for these two objectives varies when discriminating between quantum states $ |\psi_0\rangle$ and $|\psi_1\rangle $ through multiple measurements. In this study, we introduce a novel state discrimination model that reveals the intricate relationship between the average error rate and average copy consumption. By integrating these two crucial metrics and minimizing their weighted sum for any given weight value, our research underscores the infeasibility of simultaneously minimizing these metrics through local measurements with one-way communication. Our findings present a compelling trade-off curve, highlighting the advantages of achieving a balance between error rate and copy consumption in quantum discrimination tasks, offering valuable insights into the optimization of quantum resources while ensuring the accuracy of quantum state discrimination.

On capped Higgs positivity cone

Dong-Yu Hong, Zhuo-Hui Wang, Shuang-Yong Zhou

2024, 54(7): 0705. doi: 10.52396/JUSTC-2023-0159

Article Views:(97) HTML (97) Full article PDF(399)

Abstract:
The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds. It has been shown that while the positivity part of the ultraviolet (UV) partial wave unitarity leads to the Wilson coefficients living in a convex cone, further including the nonpositivity part caps the cone from above. For Higgs scattering, a capped positivity cone was obtained using a simplified, linear unitarity condition without utilizing the full internal symmetries of Higgs scattering. Here, we further implement stronger nonlinear unitarity conditions from the UV, which generically gives rise to better bounds. We show that, for the Higgs case in particular, while the nonlinear unitarity conditions per se do not enhance the bounds, the fuller use of the internal symmetries do shrink the capped positivity cone significantly. The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds. It has been shown that while the positivity part of the ultraviolet (UV) partial wave unitarity leads to the Wilson coefficients living in a convex cone, further including the nonpositivity part caps the cone from above. For Higgs scattering, a capped positivity cone was obtained using a simplified, linear unitarity condition without utilizing the full internal symmetries of Higgs scattering. Here, we further implement stronger nonlinear unitarity conditions from the UV, which generically gives rise to better bounds. We show that, for the Higgs case in particular, while the nonlinear unitarity conditions per se do not enhance the bounds, the fuller use of the internal symmetries do shrink the capped positivity cone significantly.

Large and nonlinear electric field response in a two-dimensional ferroelectric Rashba material

Li Sheng, Xiaomin Fu, Chao Jia, Xingxing Li, Qunxiang Li

2024, 54(6): 0602. doi: 10.52396/JUSTC-2024-0004

Article Views:(140) HTML (140) Full article PDF(585)

Abstract:
The achievement of electrical spin control is highly desirable. One promising strategy involves electrically modulating the Rashba spin orbital coupling effect in materials. A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors, which is crucial for preserving spin coherence and enhancing integration density. Hence, two-dimensional (2D) Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable. Herein, by employing first-principles calculations, we design a thermodynamically stable 2D Rashba semiconductor, YSbTe₃, which possesses an indirect band gap of 1.04 eV, a large Rashba constant of 1.54 eV·Å and a strong electric field response of up to 4.80 e·Å². In particular, the Rashba constant dependence on the electric field shows an unusual nonlinear relationship. At the same time, YSbTe₃ has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier (~ 0.33 eV per formula). By changing the electric polarization direction, the Rashba spin texture of YSbTe₃ can be reversed. These outstanding properties make the ferroelectric Rashba semiconductor YSbTe₃ quite promising for spintronic applications. The achievement of electrical spin control is highly desirable. One promising strategy involves electrically modulating the Rashba spin orbital coupling effect in materials. A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors, which is crucial for preserving spin coherence and enhancing integration density. Hence, two-dimensional (2D) Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable. Herein, by employing first-principles calculations, we design a thermodynamically stable 2D Rashba semiconductor, YSbTe₃, which possesses an indirect band gap of 1.04 eV, a large Rashba constant of 1.54 eV·Å and a strong electric field response of up to 4.80 e·Å². In particular, the Rashba constant dependence on the electric field shows an unusual nonlinear relationship. At the same time, YSbTe₃ has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier (~ 0.33 eV per formula). By changing the electric polarization direction, the Rashba spin texture of YSbTe₃ can be reversed. These outstanding properties make the ferroelectric Rashba semiconductor YSbTe₃ quite promising for spintronic applications.

Temperature-robust diamond magnetometry based on the double-transition method

Caijin Xie, Yunbin Zhu, Yijin Xie, Tingwei Li, Wenzhe Zhang, Yifan Wang, Xing Rong

2023, 53(7): 0701. doi: 10.52396/JUSTC-2022-0150

Article Views:(870) HTML (870) Full article PDF(3558)

Abstract:
As a promising solid-state sensor at room temperature, diamond magnetometers based on nitrogen-vacancy (NV) centers have been developed tremendously in recent years. Many studies have demonstrated its potential for achieving high spatial resolution and sensitivity. However, the temperature dependence of the zero-field splitting D of NV centers poses an enormous challenge for the application of diamond magnetometry, since it is difficult to avoid temperature drift in most application scenarios. Here, we demonstrate a type of temperature-robust diamond magnetometry based on the double-transition method. By utilizing both transitions between

\begin{document}$|m_{\rm{s}}=0\rangle$\end{document}

and

\begin{document}$|m_{\rm{s}}=\pm1\rangle$\end{document}

sublevels with incomplete degeneracy of the

\begin{document}$|m_{\rm{s}}=\pm1\rangle$\end{document}

states, the impacts of D variations induced by temperature drift can be counteracted. The drift of magnetic field measurement result has been reduced by approximately 7-fold. With further improvements, the temperature-robust diamond magnetometry has the potential to be applied in biomagnetism and space science research. As a promising solid-state sensor at room temperature, diamond magnetometers based on nitrogen-vacancy (NV) centers have been developed tremendously in recent years. Many studies have demonstrated its potential for achieving high spatial resolution and sensitivity. However, the temperature dependence of the zero-field splitting D of NV centers poses an enormous challenge for the application of diamond magnetometry, since it is difficult to avoid temperature drift in most application scenarios. Here, we demonstrate a type of temperature-robust diamond magnetometry based on the double-transition method. By utilizing both transitions between $|m_{\rm{s}}=0\rangle$ and $|m_{\rm{s}}=\pm1\rangle$ sublevels with incomplete degeneracy of the $|m_{\rm{s}}=\pm1\rangle$states, the impacts of D variations induced by temperature drift can be counteracted. The drift of magnetic field measurement result has been reduced by approximately 7-fold. With further improvements, the temperature-robust diamond magnetometry has the potential to be applied in biomagnetism and space science research.

Electronic correlation effects on stabilizing a perfect Kagome lattice and ferromagnetic fluctuation in LaRu₃Si₂

Yilin Wang

2023, 53(7): 0702. doi: 10.52396/JUSTC-2022-0182

Article Views:(749) HTML (749) Full article PDF(2506)

Abstract:
A perfect Kagome lattice features flat bands that usually lead to strong electronic correlation effects, but how electronic correlation, in turn, stabilizes a perfect Kagome lattice has rarely been explored. Here, we study this effect in a superconducting (

\begin{document}$T_{\rm{c}} \sim 7.8$\end{document}

K) Kagome metal LaRu₃Si₂ with a distorted Kagome plane consisting of pure Ru ions, using density functional theory plus

\begin{document}$ U $\end{document}

and plus dynamical mean-field theory. We find that increasing electronic correlation can stabilize a perfect Kagome lattice and induce substantial ferromagnetic fluctuations in LaRu₃Si₂. By comparing the calculated magnetic susceptibilities to experimental data, LaRu₃Si₂ is found to be on the verge of becoming a perfect Kagome lattice. It thus shows moderate but non-negligible electronic correlations and ferromagnetic fluctuations, which are crucial to understand the experimentally observed non-Fermi-liquid behavior and the pretty high superconducting

\begin{document}$T_{\rm{c}}$\end{document}

of LaRu₃Si₂. A perfect Kagome lattice features flat bands that usually lead to strong electronic correlation effects, but how electronic correlation, in turn, stabilizes a perfect Kagome lattice has rarely been explored. Here, we study this effect in a superconducting ($T_{\rm{c}} \sim 7.8$ K) Kagome metal LaRu₃Si₂ with a distorted Kagome plane consisting of pure Ru ions, using density functional theory plus $ U $ and plus dynamical mean-field theory. We find that increasing electronic correlation can stabilize a perfect Kagome lattice and induce substantial ferromagnetic fluctuations in LaRu₃Si₂. By comparing the calculated magnetic susceptibilities to experimental data, LaRu₃Si₂ is found to be on the verge of becoming a perfect Kagome lattice. It thus shows moderate but non-negligible electronic correlations and ferromagnetic fluctuations, which are crucial to understand the experimentally observed non-Fermi-liquid behavior and the pretty high superconducting $T_{\rm{c}}$ of LaRu₃Si₂.

A coherent study of e⁺e⁻→ωπ⁰, ωπ⁺π⁻, and ωη

Yan Wu, Qinsong Zhou, Wenbiao Yan, Guangshun Huang

2023, 53(7): 0704. doi: 10.52396/JUSTC-2023-0086

Article Views:(522) HTML (522) Full article PDF(2784)

Abstract:
In this work, a combined analysis is performed on the processes of

\begin{document}$e^+e^-\to\omega\pi^0\pi^0$\end{document}

,

\begin{document}$e^+e^-\to\omega\pi^+\pi^-$\end{document}

, and

\begin{document}$e^+e^-\to\omega\eta$\end{document}

to study possible

\begin{document}$\omega$\end{document}

excited states at approximately 2.2 GeV. The resonance parameters are extracted by simultaneous fits of the Born cross section line shapes of these processes. In the fit with one resonance, the mass and width are fitted to be

\begin{document}$(2207\pm14)$\end{document}

MeV

\begin{document}$/c^2$\end{document}

and

\begin{document}$(104\pm16)$\end{document}

MeV, respectively. The result is consistent with previous measurements. In the fit with two resonances, the mass and width for the first resonance are fitted to be

\begin{document}$(2160\pm36)$\end{document}

MeV

\begin{document}$/c^2$\end{document}

(solution I),

\begin{document}$(2154\pm12)$\end{document}

MeV

\begin{document}$/c^2$\end{document}

(solution II) and

\begin{document}$(141\pm74)$\end{document}

MeV (solution I),

\begin{document}$(152\pm77)$\end{document}

MeV (solution II), respectively. The mass and width for the second resonance are fitted to be

\begin{document}$(2298\pm19)$\end{document}

MeV

\begin{document}$/c^2$\end{document}

(solution I),

\begin{document}$(2309\pm6)$\end{document}

MeV

\begin{document}$/c^2$\end{document}

(solution II) and

\begin{document}$(106\pm77)$\end{document}

MeV (solution I),

\begin{document}$(99\pm23)$\end{document}

MeV (solution II), respectively. The result is consistent with the theoretical prediction of

\begin{document}$\omega(4S)$\end{document}

and

\begin{document}$\omega(3D)$\end{document}

. The intermediate subprocesses in

\begin{document}$e^+e^-\to\omega\pi^+\pi^-$\end{document}

are analyzed using the resonance parameters of the previous fits in this work. In the fit with one resonance, the fitting result of

\begin{document}$\varGamma^{e^+e^-}_{{\rm{R}}}B_{{\rm{R}}}$\end{document}

is partially consistent with the previous result. In the fit with two resonances, the fitting result of

\begin{document}$\varGamma^{e^+e^-}_{{\rm{R}}}B_{{\rm{R}}}$\end{document}

is of the same order of magnitude as the theoretical prediction. This work may provide useful information for studying the light flavor vector meson family. In this work, a combined analysis is performed on the processes of $e^+e^-\to\omega\pi^0\pi^0$, $e^+e^-\to\omega\pi^+\pi^-$, and $e^+e^-\to\omega\eta$ to study possible $\omega$ excited states at approximately 2.2 GeV. The resonance parameters are extracted by simultaneous fits of the Born cross section line shapes of these processes. In the fit with one resonance, the mass and width are fitted to be $(2207\pm14)$ MeV$/c^2$ and $(104\pm16)$ MeV, respectively. The result is consistent with previous measurements. In the fit with two resonances, the mass and width for the first resonance are fitted to be $(2160\pm36)$ MeV$/c^2$ (solution I), $(2154\pm12)$ MeV$/c^2$ (solution II) and $(141\pm74)$ MeV (solution I), $(152\pm77)$ MeV (solution II), respectively. The mass and width for the second resonance are fitted to be $(2298\pm19)$ MeV$/c^2$ (solution I), $(2309\pm6)$ MeV$/c^2$ (solution II) and $(106\pm77)$ MeV (solution I), $(99\pm23)$ MeV (solution II), respectively. The result is consistent with the theoretical prediction of $\omega(4S)$ and $\omega(3D)$. The intermediate subprocesses in $e^+e^-\to\omega\pi^+\pi^-$ are analyzed using the resonance parameters of the previous fits in this work. In the fit with one resonance, the fitting result of $\varGamma^{e^+e^-}_{{\rm{R}}}B_{{\rm{R}}}$ is partially consistent with the previous result. In the fit with two resonances, the fitting result of $\varGamma^{e^+e^-}_{{\rm{R}}}B_{{\rm{R}}}$ is of the same order of magnitude as the theoretical prediction. This work may provide useful information for studying the light flavor vector meson family.

Design of a fiber cavity ion trap for a high-efficiency and high-rate quantum network node

Xing-Yu Bao, Jin-Ming Cui, Ding Fang, Wei-Bin Chen, Jian Wang, Yun-Feng Huang, Chuan-Feng Li, Guang-Can Guo

2023, 53(7): 0705. doi: 10.52396/JUSTC-2023-0005

Article Views:(795) HTML (795) Full article PDF(2412)

Abstract:
The main purpose of this paper is to design a novel coupled system of an ion trap and a fiber cavity. This integrated solution is achieved by fabricating a fiber cavity with a metal mask on the side and end faces of the fiber. The fiber cavity with the metal mask can transmit light and electric charges, and the metal mask on the fiber end-face can shield electric charges on the dielectric high-reflection film. This system is designed to trap a single

\begin{document}$ ^{138}\text{Ba}^{+} $\end{document}

ion and realize coupling of the fiber cavity to the fluorescence at a 493 nm wavelength of

\begin{document}$ ^{138}\text{Ba}^{+} $\end{document}

. To efficiently collect fluorescent photons, we perform a theoretical analysis of the overall system to achieve optimal coupling of each individual part. The cavity length is designed to be

\begin{document}$ 250 $\end{document}

μm, and the optimized coupling parameters are

\begin{document}$(g,\kappa,\gamma)/2{\text{π}}=(55,\;105,\;20)$\end{document}

MHz. We also improve the stability and reliability of the system by analyzing the vibration, performance of the ion trap, and thermal stability. The core of the system is composed of materials with similar thermal expansion coefficients to improve thermal stability. The system uses spring connections to isolate vibrations inside and outside the vacuum chamber. We theoretically solve the difficulties of manufacturing the coupled system and have completed the experimental verification of some key technologies. The whole system is expected to be extended into a complex quantum network system to realize quantum computation and communication. The main purpose of this paper is to design a novel coupled system of an ion trap and a fiber cavity. This integrated solution is achieved by fabricating a fiber cavity with a metal mask on the side and end faces of the fiber. The fiber cavity with the metal mask can transmit light and electric charges, and the metal mask on the fiber end-face can shield electric charges on the dielectric high-reflection film. This system is designed to trap a single $ ^{138}\text{Ba}^{+} $ ion and realize coupling of the fiber cavity to the fluorescence at a 493 nm wavelength of $ ^{138}\text{Ba}^{+} $. To efficiently collect fluorescent photons, we perform a theoretical analysis of the overall system to achieve optimal coupling of each individual part. The cavity length is designed to be $ 250 $ μm, and the optimized coupling parameters are $(g,\kappa,\gamma)/2{\text{π}}=(55,\;105,\;20)$ MHz. We also improve the stability and reliability of the system by analyzing the vibration, performance of the ion trap, and thermal stability. The core of the system is composed of materials with similar thermal expansion coefficients to improve thermal stability. The system uses spring connections to isolate vibrations inside and outside the vacuum chamber. We theoretically solve the difficulties of manufacturing the coupled system and have completed the experimental verification of some key technologies. The whole system is expected to be extended into a complex quantum network system to realize quantum computation and communication.

Controlled properties of perovskite oxide films by engineering oxygen octahedral rotation

Junhua Liu, Xiaofei Gao, Wen Xiao, Shilin Hu, Yaoyao Ji, Lin Li, Kai Chen, Zhaoliang Liao

2023, 53(1): 1. doi: 10.52396/JUSTC-2022-0101

Article Views:(1120) HTML (1120) Full article PDF(2017)

Abstract:
Complex perovskite oxides exhibit extremely rich physical properties in terms of magnetism, electrical transport, and electrical polarization characteristics due to the competition and coupling of many degrees of freedom. The B-site ions and O ions in perovskite form six-coordinated octahedral units, which are connected at a common vertex toward the basic framework of the perovskite oxide, providing a crucial platform to tailor physical properties. The rotation or distortion of the oxygen octahedra will tip the competing balance, leading to many emergent ground states. To further clarify the subtle relationship between emergent properties and oxide octahedral behavior, this article reviews the structure of perovskite oxides, the characterization methods of oxygen octahedral rotation and the response of transport, electrical polarization and magnetism of several typical perovskite heterostructures to oxygen octahedral rotation modes. With knowledge of how to manipulate the octahedral rotation behavior and regulate the physical properties of perovskite oxides, rationally designing the sample manufacturing process can effectively guide the development and application of novel electronic functional materials and devices. Complex perovskite oxides exhibit extremely rich physical properties in terms of magnetism, electrical transport, and electrical polarization characteristics due to the competition and coupling of many degrees of freedom. The B-site ions and O ions in perovskite form six-coordinated octahedral units, which are connected at a common vertex toward the basic framework of the perovskite oxide, providing a crucial platform to tailor physical properties. The rotation or distortion of the oxygen octahedra will tip the competing balance, leading to many emergent ground states. To further clarify the subtle relationship between emergent properties and oxide octahedral behavior, this article reviews the structure of perovskite oxides, the characterization methods of oxygen octahedral rotation and the response of transport, electrical polarization and magnetism of several typical perovskite heterostructures to oxygen octahedral rotation modes. With knowledge of how to manipulate the octahedral rotation behavior and regulate the physical properties of perovskite oxides, rationally designing the sample manufacturing process can effectively guide the development and application of novel electronic functional materials and devices.

Twisted plasma waves driven by twisted ponderomotive force

Yin Shi, David R Blackman, Robert J Kingham, Alexey Arefiev

2023, 53(1): 3. doi: 10.52396/JUSTC-2022-0080

Article Views:(634) HTML (634) Full article PDF(1864)

Abstract:
We present the results of twisted plasma waves driven by twisted ponderomotive force. With the beating of two, co-propagating, Laguerre-Gaussian (LG) orbital angular momentum (OAM) laser pulses with different frequencies and also different twist indices, we can obtain the twisted ponderomotive force. Three-dimensional particle-in-cell simulations are used to demonstrate the twisted plasma waves driven by lasers. The twisted plasma waves have an electron density perturbation with a helical rotating structure. Different from the predictions of the linear fluid theory, the simulation results show a nonlinear rotating current and a static axial magnetic field. Along with the rotating current is the axial OAM carried by particles in the twisted plasma waves. A detailed theoretical analysis of twisted plasma waves is also given. We present the results of twisted plasma waves driven by twisted ponderomotive force. With the beating of two, co-propagating, Laguerre-Gaussian (LG) orbital angular momentum (OAM) laser pulses with different frequencies and also different twist indices, we can obtain the twisted ponderomotive force. Three-dimensional particle-in-cell simulations are used to demonstrate the twisted plasma waves driven by lasers. The twisted plasma waves have an electron density perturbation with a helical rotating structure. Different from the predictions of the linear fluid theory, the simulation results show a nonlinear rotating current and a static axial magnetic field. Along with the rotating current is the axial OAM carried by particles in the twisted plasma waves. A detailed theoretical analysis of twisted plasma waves is also given.

Physics

STAY CONNECTED

News

JUSTC Culture

Authors

Browse

Contact Us

About