Xuelian Zhang, Zhenyu Zhao, Rajour Tanyi Ako, Sharath Sriram, Xuan Zhao, Hongxin Liu, Haijun Bu
The control of the speed of terahertz waves is always a challenge since the bandgap of most optical materials is much larger beyond meV with subtle nonlinear susceptibility. Moiré metasurfaces are shown to exhibit wide tunable optical properties and extraordinary physical phenomena at specific commensurate angles. These can be achieved by a careful design of the metasurface to manipulate terahertz slow light. Herein, we demonstrate a triple layer Moiré metasurface with a distinct electromagnetically induced transparency (EIT) phenomenon at commensurate angles. The proposed metasurface is composed of an intrinsic square lattice embedded into another Moiré photonic superlattice made of twisted square lattice at commensurate angles of 10.39° and 7.63°. The coupling between adjacent meta-atoms on the combined metasurface leads to destructive interference of dual trapped lattice modes, which results in a transparency window at the terahertz band. A maximum group delay of 9.76 ps is found at the transparent window of 0.84 THz when the commensurate angle is 10.39°. When the commensurate angle reduces to 7.63°, the transparency window shifts to 0.57 THz with a 5.96 ps group delay. The coupled Lorentz oscillator model indicates that the nonlinear optical susceptibility at transparency windows is above zero. Our results create an approach to tune the EIT as well as slow light in the terahertz band. Our device can have potential applications in terahertz signal processing and storage.
{"title":"Moiré photonic superlattice-induced transparency at commensurate angle in a terahertz metasurface composed of triple layer square lattices","authors":"Xuelian Zhang, Zhenyu Zhao, Rajour Tanyi Ako, Sharath Sriram, Xuan Zhao, Hongxin Liu, Haijun Bu","doi":"10.1063/5.0229684","DOIUrl":"https://doi.org/10.1063/5.0229684","url":null,"abstract":"The control of the speed of terahertz waves is always a challenge since the bandgap of most optical materials is much larger beyond meV with subtle nonlinear susceptibility. Moiré metasurfaces are shown to exhibit wide tunable optical properties and extraordinary physical phenomena at specific commensurate angles. These can be achieved by a careful design of the metasurface to manipulate terahertz slow light. Herein, we demonstrate a triple layer Moiré metasurface with a distinct electromagnetically induced transparency (EIT) phenomenon at commensurate angles. The proposed metasurface is composed of an intrinsic square lattice embedded into another Moiré photonic superlattice made of twisted square lattice at commensurate angles of 10.39° and 7.63°. The coupling between adjacent meta-atoms on the combined metasurface leads to destructive interference of dual trapped lattice modes, which results in a transparency window at the terahertz band. A maximum group delay of 9.76 ps is found at the transparent window of 0.84 THz when the commensurate angle is 10.39°. When the commensurate angle reduces to 7.63°, the transparency window shifts to 0.57 THz with a 5.96 ps group delay. The coupled Lorentz oscillator model indicates that the nonlinear optical susceptibility at transparency windows is above zero. Our results create an approach to tune the EIT as well as slow light in the terahertz band. Our device can have potential applications in terahertz signal processing and storage.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142363092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lu Yang, Ziqian Sheng, Siliang Kuang, Wenjing Xu, Yaxin He, Xu Zhang, Xiangyu Xu, Kelvin H. L. Zhang
GaN-based ultraviolet light emitting diodes (UV LEDs) have attracted considerable attention in recent years and are required in various applications such as healthcare, light illumination, and optical communication. However, the limited UV transparency of the electrodes like indium-doped tin oxide has hindered the external quantum efficiency of current UV LEDs. In this work, we present the growth of UV-transparent Ta-doped SnO2 (TTO) thin films on GaN as a promising UV-transparent electrode for LEDs. TTO thin films with a thickness of 200 nm exhibit optical transmission exceeding 80% at the wavelength of 300 nm, with a low resistivity of 2.5 × 10−4 Ω·cm and a low contact resistance of 1.7 × 10−2 Ω cm2 to n-type GaN. High-resolution x-ray photoemission spectra were employed to reveal insight into the electronic structure of TTO and the interfacial band alignment of TTO/GaN heterojunction. The wide optical bandgap (∼4.6 eV) and high UV transparency of TTO films stem from a significant Burstein–Moss shift due to degenerate doping, giving rise to metal-like characteristics and a small barrier height at the interface of TTO/GaN. These findings imply the origin of low contact resistivity of TTO to n-type GaN and may be applicable to the development of UV-transparent electrodes of optoelectronic devices.
近年来，氮化镓基紫外发光二极管（UV LED）备受关注，并被广泛应用于医疗保健、光照和光通信等领域。然而，掺铟锡氧化物等电极的紫外透明性有限，阻碍了当前紫外发光二极管的外部量子效率。在这项工作中，我们在氮化镓上生长了紫外透明的掺钽二氧化锡（TTO）薄膜，作为一种很有前景的 LED 紫外透明电极。厚度为 200 nm 的 TTO 薄膜在 300 nm 波长下的光透射率超过 80%，电阻率低至 2.5 × 10-4 Ω-cm，与 n 型 GaN 的接触电阻低至 1.7 × 10-2 Ω cm2。高分辨率 X 射线光发射光谱揭示了 TTO 的电子结构以及 TTO/GaN 异质结的界面带排列。TTO 薄膜的宽光带隙（∼4.6 eV）和高紫外透明性源于退行性掺杂导致的显著伯斯坦-莫斯偏移，从而在 TTO/GaN 的界面上产生了类似金属的特性和较小的势垒高度。这些发现暗示了 TTO 与 n 型氮化镓低接触电阻率的起源，并可能适用于开发光电设备的紫外透明电极。
{"title":"Growth of Ta-doped SnO2 on GaN as a UV-transparent conducting electrode and band alignment properties of the heterojunction","authors":"Lu Yang, Ziqian Sheng, Siliang Kuang, Wenjing Xu, Yaxin He, Xu Zhang, Xiangyu Xu, Kelvin H. L. Zhang","doi":"10.1063/5.0213093","DOIUrl":"https://doi.org/10.1063/5.0213093","url":null,"abstract":"GaN-based ultraviolet light emitting diodes (UV LEDs) have attracted considerable attention in recent years and are required in various applications such as healthcare, light illumination, and optical communication. However, the limited UV transparency of the electrodes like indium-doped tin oxide has hindered the external quantum efficiency of current UV LEDs. In this work, we present the growth of UV-transparent Ta-doped SnO2 (TTO) thin films on GaN as a promising UV-transparent electrode for LEDs. TTO thin films with a thickness of 200 nm exhibit optical transmission exceeding 80% at the wavelength of 300 nm, with a low resistivity of 2.5 × 10−4 Ω·cm and a low contact resistance of 1.7 × 10−2 Ω cm2 to n-type GaN. High-resolution x-ray photoemission spectra were employed to reveal insight into the electronic structure of TTO and the interfacial band alignment of TTO/GaN heterojunction. The wide optical bandgap (∼4.6 eV) and high UV transparency of TTO films stem from a significant Burstein–Moss shift due to degenerate doping, giving rise to metal-like characteristics and a small barrier height at the interface of TTO/GaN. These findings imply the origin of low contact resistivity of TTO to n-type GaN and may be applicable to the development of UV-transparent electrodes of optoelectronic devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142363088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SrAl2O4:Eu2+, Dy3+ as an excellent persistent phosphor has been widely applied in many fields. However, the high temperature induced thermal failure has always been a bottleneck problem restricting its long-term development. In this study, a simple pre-annealing method was utilized to improve the thermal damage resistance ability of SrAl2O4:Eu2+, Dy3+ persistent phosphors. After annealing at 900 °C, the afterglow duration time of the phosphor pre-annealed at 400 °C reached 233 min, which was twice longer than that of the phosphor without pre-annealing. An extrinsic vacancy defect migration theory at an elevated temperature was proposed to explain the interesting phenomenon. This study introduced a path to enhance the thermal stability of SrAl2O4:Eu2+, Dy3+ persistent phosphors and provided a thought to design persistent luminescence materials with desired thermal stability.
{"title":"Improvement of thermal damage resistance of SrAl2O4:Eu2+, Dy3+ persistent phosphor by a low temperature pre-annealing and its mechanism","authors":"Dongshun Chen, Tianyuan Zhou, Le Zhang, Wen Tian, Xinyuan Zhang, Chaofan Shi, Hongsen Wang, Zihan Zhou, Baojin Huang, Wieslaw Strek, Hao Chen","doi":"10.1063/5.0233664","DOIUrl":"https://doi.org/10.1063/5.0233664","url":null,"abstract":"SrAl2O4:Eu2+, Dy3+ as an excellent persistent phosphor has been widely applied in many fields. However, the high temperature induced thermal failure has always been a bottleneck problem restricting its long-term development. In this study, a simple pre-annealing method was utilized to improve the thermal damage resistance ability of SrAl2O4:Eu2+, Dy3+ persistent phosphors. After annealing at 900 °C, the afterglow duration time of the phosphor pre-annealed at 400 °C reached 233 min, which was twice longer than that of the phosphor without pre-annealing. An extrinsic vacancy defect migration theory at an elevated temperature was proposed to explain the interesting phenomenon. This study introduced a path to enhance the thermal stability of SrAl2O4:Eu2+, Dy3+ persistent phosphors and provided a thought to design persistent luminescence materials with desired thermal stability.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142363091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Johannes Mohr, Kiumars Aryana, Md. Rafiqul Islam, Dirk J. Wouters, Rainer Waser, Patrick E. Hopkins, Joyeeta Nag, Daniel Bedau
Understanding the thermal conductivity of chromium-doped V2O3 is crucial for optimizing the design of selectors for memory and neuromorphic devices. We utilized the time-domain thermoreflectance technique to measure the thermal conductivity of chromium-doped V2O3 across varying concentrations, spanning the doping-induced metal–insulator transition. In addition, different oxygen stoichiometries and film thicknesses were investigated in their crystalline and amorphous phases. Chromium doping concentration (0%–30%) and the degree of crystallinity emerged as the predominant factors influencing the thermal properties, while the effect of oxygen flow (600–1400 ppm) during deposition proved to be negligible. Our observations indicate that even in the metallic phase of V2O3, the lattice contribution is the dominant factor in thermal transport with no observable impact from the electrons on heat transport. Finally, the thermal conductivity of both amorphous and crystalline V2O3 was measured at cryogenic temperatures (80–450 K). Our thermal conductivity measurements as a function of temperature reveal that both phases exhibit behavior similar to amorphous materials, indicating pronounced phonon scattering effects in the crystalline phase of V2O3.
{"title":"Electronic vs phononic thermal transport in Cr-doped V2O3 thin films across the Mott transition","authors":"Johannes Mohr, Kiumars Aryana, Md. Rafiqul Islam, Dirk J. Wouters, Rainer Waser, Patrick E. Hopkins, Joyeeta Nag, Daniel Bedau","doi":"10.1063/5.0231707","DOIUrl":"https://doi.org/10.1063/5.0231707","url":null,"abstract":"Understanding the thermal conductivity of chromium-doped V2O3 is crucial for optimizing the design of selectors for memory and neuromorphic devices. We utilized the time-domain thermoreflectance technique to measure the thermal conductivity of chromium-doped V2O3 across varying concentrations, spanning the doping-induced metal–insulator transition. In addition, different oxygen stoichiometries and film thicknesses were investigated in their crystalline and amorphous phases. Chromium doping concentration (0%–30%) and the degree of crystallinity emerged as the predominant factors influencing the thermal properties, while the effect of oxygen flow (600–1400 ppm) during deposition proved to be negligible. Our observations indicate that even in the metallic phase of V2O3, the lattice contribution is the dominant factor in thermal transport with no observable impact from the electrons on heat transport. Finally, the thermal conductivity of both amorphous and crystalline V2O3 was measured at cryogenic temperatures (80–450 K). Our thermal conductivity measurements as a function of temperature reveal that both phases exhibit behavior similar to amorphous materials, indicating pronounced phonon scattering effects in the crystalline phase of V2O3.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The exceptional performance of GaN semiconductors in lasers, wireless communication, and energy storage systems makes them crucial for future multi-functional devices. However, during the polishing of GaN wafers, abrasive particles can induce subsurface damage, compromising device performance. This study investigates dislocation loops in GaN single crystal to understand dislocation nucleation and glide under external stress. Using nanoindentation for compressive stress, we confirmed multiple slip system activation via transmission electron microscopy after pop-in. We also performed molecular dynamics to simulate the nucleation and multiplication of U-shaped dislocation loops. Furthermore, we developed a theoretical model using Peierls–Nabarro stress to quantify GaN's critical shear stress. Raman spectroscopy was also used to analyze shear stress on U-shaped loops, supporting our model. This study provides insights into GaN dislocation dynamics under mechanical stress, aiding in wafer defect evaluation during machining and offering guidance for dislocation evolution.
氮化镓半导体在激光器、无线通信和储能系统中的卓越性能使其成为未来多功能设备的关键。然而，在氮化镓晶片的抛光过程中，磨料颗粒会导致次表面损伤，从而影响器件性能。本研究调查了氮化镓单晶中的位错环，以了解位错在外部应力作用下的成核和滑行。我们利用纳米压痕法获得压应力，并通过透射电子显微镜确认了弹入后的多滑移系统激活。我们还利用分子动力学模拟了 U 形位错环的成核和倍增。此外，我们还利用 Peierls-Nabarro 应力建立了一个理论模型，以量化 GaN 的临界剪切应力。我们还利用拉曼光谱分析了 U 形环的剪切应力，为我们的模型提供了支持。这项研究深入揭示了 GaN 位错在机械应力下的动态，有助于在加工过程中评估晶片缺陷，并为位错演化提供指导。
{"title":"Dislocation evolution in anisotropic deformation of GaN under nanoindentation","authors":"Kebei Chen, Mengfei Xue, Runkun Chen, Xiaoming Dong, Xiaodong Gao, Jianfeng Wang, Sha Han, Wentao Song, Ke Xu","doi":"10.1063/5.0230366","DOIUrl":"https://doi.org/10.1063/5.0230366","url":null,"abstract":"The exceptional performance of GaN semiconductors in lasers, wireless communication, and energy storage systems makes them crucial for future multi-functional devices. However, during the polishing of GaN wafers, abrasive particles can induce subsurface damage, compromising device performance. This study investigates dislocation loops in GaN single crystal to understand dislocation nucleation and glide under external stress. Using nanoindentation for compressive stress, we confirmed multiple slip system activation via transmission electron microscopy after pop-in. We also performed molecular dynamics to simulate the nucleation and multiplication of U-shaped dislocation loops. Furthermore, we developed a theoretical model using Peierls–Nabarro stress to quantify GaN's critical shear stress. Raman spectroscopy was also used to analyze shear stress on U-shaped loops, supporting our model. This study provides insights into GaN dislocation dynamics under mechanical stress, aiding in wafer defect evaluation during machining and offering guidance for dislocation evolution.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The nitrogen-vacancy (NV) centers ensemble has extensive application prospects in vector-magnetic-field measurement due to its accurate and fixed spatial orientations along the crystallographic axes of diamonds. However, to address signals of NV centers along all four axes, a large bias magnetic field sufficient to spectrally separate their resonances is typically inevitable, which may affect the magnetic substance under test and require multiple-frequency microwaves to interrogate signals of the four axes. Here, we demonstrate an NV-based simultaneous vector magnetometer that works at a bias field as low as just separating the resonant peaks of |ms=±1 states and utilizes a single-frequency microwave. By simultaneously detecting the fluorescence at specific optical polarization angles in three orthogonal directions and determining the transformation matrix in advance, all the Cartesian components of the magnetic field under test are distinguished. The experimentally achieved magnetic-field sensitivity is 63 nT/Hz, and the bias field is reduced to around 11 Gauss (still reducible by narrowing the linewidth) in ambient conditions. The proposed methods dramatically reduce the bias field for NV-based simultaneous vector magnetometers and potentially expand their applications in biological science, materials science, and industrial noninvasive detection.
{"title":"Simultaneous vector magnetometry based on fluorescence polarization of NV centers ensemble in diamond","authors":"Mingxin Li, Heng Yuan, Pengcheng Fan, Sixian Wang, Jihongbo Shen, Lixia Xu","doi":"10.1063/5.0220694","DOIUrl":"https://doi.org/10.1063/5.0220694","url":null,"abstract":"The nitrogen-vacancy (NV) centers ensemble has extensive application prospects in vector-magnetic-field measurement due to its accurate and fixed spatial orientations along the crystallographic axes of diamonds. However, to address signals of NV centers along all four axes, a large bias magnetic field sufficient to spectrally separate their resonances is typically inevitable, which may affect the magnetic substance under test and require multiple-frequency microwaves to interrogate signals of the four axes. Here, we demonstrate an NV-based simultaneous vector magnetometer that works at a bias field as low as just separating the resonant peaks of |ms=±1 states and utilizes a single-frequency microwave. By simultaneously detecting the fluorescence at specific optical polarization angles in three orthogonal directions and determining the transformation matrix in advance, all the Cartesian components of the magnetic field under test are distinguished. The experimentally achieved magnetic-field sensitivity is 63 nT/Hz, and the bias field is reduced to around 11 Gauss (still reducible by narrowing the linewidth) in ambient conditions. The proposed methods dramatically reduce the bias field for NV-based simultaneous vector magnetometers and potentially expand their applications in biological science, materials science, and industrial noninvasive detection.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lei Li, Sihan Yan, Wanyu Ma, Jia-Han Zhang, Shaohui Zhang, Mingming Jiang, Lingfeng Gao, Weihua Tang, Zeng Liu
Polarization-sensitive photodetection has promising prospects for civilian and military applications based on anisotropic semiconductors. However, it is greatly limited due to the lack of valid materials as well as the terrible linear dichroism ratio. In this Letter, a metal–oxide–semiconductor β-Ga2O3 with strong anisotropic property is proposed for highly efficient polarizing detection, which can potentially overcome these limitations. Angle-resolved polarization Raman spectroscopy was performed to confirm excellent anisotropic phonon vibration. Unique narrow solar-blind polarization-sensitive photo-absorption (240–270 nm) can be observed, which can be attributed to the natural anisotropy, referring in particular to the polarization-resolved absorption in the surround of the bandgap of β-Ga2O3. Benefiting from the structural anisotropy, the polarization-sensitive photodetector exhibits an excellent linear dichroic ratio of ∼1.8. Moreover, obvious color change is observed under different polarized angles, providing great potential in polarization imaging. With these advantages, we anticipated that this research will pave avenues for the fabrication of polarization-sensitive solar-blind UV photodetectors.
{"title":"Angle-resolved polarization Raman spectroscopy of β-Ga2O3 and their application in sensitive solar-blind photodetection","authors":"Lei Li, Sihan Yan, Wanyu Ma, Jia-Han Zhang, Shaohui Zhang, Mingming Jiang, Lingfeng Gao, Weihua Tang, Zeng Liu","doi":"10.1063/5.0223518","DOIUrl":"https://doi.org/10.1063/5.0223518","url":null,"abstract":"Polarization-sensitive photodetection has promising prospects for civilian and military applications based on anisotropic semiconductors. However, it is greatly limited due to the lack of valid materials as well as the terrible linear dichroism ratio. In this Letter, a metal–oxide–semiconductor β-Ga2O3 with strong anisotropic property is proposed for highly efficient polarizing detection, which can potentially overcome these limitations. Angle-resolved polarization Raman spectroscopy was performed to confirm excellent anisotropic phonon vibration. Unique narrow solar-blind polarization-sensitive photo-absorption (240–270 nm) can be observed, which can be attributed to the natural anisotropy, referring in particular to the polarization-resolved absorption in the surround of the bandgap of β-Ga2O3. Benefiting from the structural anisotropy, the polarization-sensitive photodetector exhibits an excellent linear dichroic ratio of ∼1.8. Moreover, obvious color change is observed under different polarized angles, providing great potential in polarization imaging. With these advantages, we anticipated that this research will pave avenues for the fabrication of polarization-sensitive solar-blind UV photodetectors.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guillaume Beaulieu, Zhaochu Luo, Víctor Raposo, Laura J. Heyderman, Pietro Gambardella, Eduardo Martínez, Aleš Hrabec
The interfacial Dzyaloshinskii–Moriya interaction (DMI) can be exploited in magnetic thin films to realize lateral chirally coupled systems, providing a way to couple different sections of a magnetic racetrack and realize interconnected networks of magnetic logic gates. Here, we systematically investigate the interplay between spin–orbit torques, chiral coupling, and the device design in domain wall racetracks. We show that the current-induced domain nucleation process can be tuned between single-domain nucleation and repeated nucleation of alternate domains by changing the orientation of an in-plane patterned magnetic region within an out-of-plane magnetic racetrack. Furthermore, by combining experiments and micromagnetic simulations, we show that the combination of damping-like and field-like spin–orbit torques with DMI results in selective domain wall injection in one of two arms of a Y-shaped device depending on the current density. Such an element constitutes the basis of domain wall based demultiplexer, which is essential for distributing a single input to any one of the multiple outputs in logic circuits. Our results provide input for the design of reliable and multifunctional domain wall circuits based on chirally coupled interfaces.
在磁性薄膜中可以利用界面上的 Dzyaloshinskii-Moriya 相互作用（DMI）来实现横向手性耦合系统，从而为磁性赛道的不同部分耦合以及实现磁性逻辑门的互连网络提供了一种方法。在这里，我们系统地研究了自旋轨道力矩、手性耦合以及畴壁赛道中器件设计之间的相互作用。我们的研究表明，通过改变平面外磁赛道中平面内图案化磁区的方向，可以在单个磁畴成核和交替磁畴重复成核之间调整电流诱导的磁畴成核过程。此外，通过将实验和微磁模拟相结合，我们证明了阻尼样和磁场样自旋轨道力矩与 DMI 的结合会导致根据电流密度在 Y 形器件的两臂之一选择性地注入畴壁。这种元件构成了基于畴壁的解复用器的基础，而解复用器对于将单个输入分配到逻辑电路中多个输出中的任意一个是必不可少的。我们的研究成果为设计基于手性耦合接口的可靠多功能畴壁电路提供了参考。
{"title":"Control of spin–orbit torque-driven domain nucleation through geometry in chirally coupled magnetic tracks","authors":"Guillaume Beaulieu, Zhaochu Luo, Víctor Raposo, Laura J. Heyderman, Pietro Gambardella, Eduardo Martínez, Aleš Hrabec","doi":"10.1063/5.0224146","DOIUrl":"https://doi.org/10.1063/5.0224146","url":null,"abstract":"The interfacial Dzyaloshinskii–Moriya interaction (DMI) can be exploited in magnetic thin films to realize lateral chirally coupled systems, providing a way to couple different sections of a magnetic racetrack and realize interconnected networks of magnetic logic gates. Here, we systematically investigate the interplay between spin–orbit torques, chiral coupling, and the device design in domain wall racetracks. We show that the current-induced domain nucleation process can be tuned between single-domain nucleation and repeated nucleation of alternate domains by changing the orientation of an in-plane patterned magnetic region within an out-of-plane magnetic racetrack. Furthermore, by combining experiments and micromagnetic simulations, we show that the combination of damping-like and field-like spin–orbit torques with DMI results in selective domain wall injection in one of two arms of a Y-shaped device depending on the current density. Such an element constitutes the basis of domain wall based demultiplexer, which is essential for distributing a single input to any one of the multiple outputs in logic circuits. Our results provide input for the design of reliable and multifunctional domain wall circuits based on chirally coupled interfaces.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martijn Janse, Eli van der Bent, Mart Laurman, Robert Smit, Bas Hensen
Microscopic levitated objects are a promising platform for inertial sensing, testing gravity at small scales, optomechanics in the quantum regime, and large-mass superpositions. However, existing levitation techniques harnessing optical and electrical fields suffer from noise induced by elevated internal temperatures and charge noise, respectively. Meissner-based magnetic levitation circumvents both sources of decoherence but requires cryogenic environments. Here, we characterize a sub-milligram ferromagnetic cube levitated in an alternating-current planar magnetic Paul trap at room temperature. We show behavior in line with the Mathieu equations and quality factors of up to 2500 for the librational modes. Besides technological sensing applications, this technique sets out a path for megahertz librational modes in the micrometer-sized particle limit and can be extended by implementing superconducting traps in cryogenic environments, allowing for magnetic coupling to superconducting circuits and spin-based quantum systems.
{"title":"Characterization of a levitated sub-milligram ferromagnetic cube in a planar alternating-current magnetic Paul trap","authors":"Martijn Janse, Eli van der Bent, Mart Laurman, Robert Smit, Bas Hensen","doi":"10.1063/5.0233291","DOIUrl":"https://doi.org/10.1063/5.0233291","url":null,"abstract":"Microscopic levitated objects are a promising platform for inertial sensing, testing gravity at small scales, optomechanics in the quantum regime, and large-mass superpositions. However, existing levitation techniques harnessing optical and electrical fields suffer from noise induced by elevated internal temperatures and charge noise, respectively. Meissner-based magnetic levitation circumvents both sources of decoherence but requires cryogenic environments. Here, we characterize a sub-milligram ferromagnetic cube levitated in an alternating-current planar magnetic Paul trap at room temperature. We show behavior in line with the Mathieu equations and quality factors of up to 2500 for the librational modes. Besides technological sensing applications, this technique sets out a path for megahertz librational modes in the micrometer-sized particle limit and can be extended by implementing superconducting traps in cryogenic environments, allowing for magnetic coupling to superconducting circuits and spin-based quantum systems.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. M. Backes, P. K. Elgee, K.-J. LeBlanc, C. T. Fancher, D. H. Meyer, P. D. Kunz, N. Malvania, K. L. Nicolich, J. C. Hill, B. L. Schmittberger Marlow, K. C. Cox
Rydberg atom electric field sensors are tunable quantum sensors that can perform sensitive radio frequency measurements. Their qualities have piqued interest at longer wavelengths where their small size compares favorably to impedance-matched antennas. Here, we compare the signal detection sensitivity of cm-scale Rydberg sensors to similarly sized room-temperature electrically small antennas with active and passive receiver backends. We present and analyze effective circuit models for each sensor type, facilitating a fair sensitivity comparison for cm-scale sensors. We calculate that contemporary Rydberg sensor implementations are less sensitive than unmatched antennas with active amplification. However, we find that idealized Rydberg sensors operating with a maximized atom number and at the standard quantum limit may perform well beyond the capabilities of antenna-based sensors at room temperature, the sensitivities of both lying below typical atmospheric background noise.
{"title":"Performance of antenna-based and Rydberg quantum RF sensors in the electrically small regime","authors":"K. M. Backes, P. K. Elgee, K.-J. LeBlanc, C. T. Fancher, D. H. Meyer, P. D. Kunz, N. Malvania, K. L. Nicolich, J. C. Hill, B. L. Schmittberger Marlow, K. C. Cox","doi":"10.1063/5.0222827","DOIUrl":"https://doi.org/10.1063/5.0222827","url":null,"abstract":"Rydberg atom electric field sensors are tunable quantum sensors that can perform sensitive radio frequency measurements. Their qualities have piqued interest at longer wavelengths where their small size compares favorably to impedance-matched antennas. Here, we compare the signal detection sensitivity of cm-scale Rydberg sensors to similarly sized room-temperature electrically small antennas with active and passive receiver backends. We present and analyze effective circuit models for each sensor type, facilitating a fair sensitivity comparison for cm-scale sensors. We calculate that contemporary Rydberg sensor implementations are less sensitive than unmatched antennas with active amplification. However, we find that idealized Rydberg sensors operating with a maximized atom number and at the standard quantum limit may perform well beyond the capabilities of antenna-based sensors at room temperature, the sensitivities of both lying below typical atmospheric background noise.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142360148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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