Pub Date : 2024-09-01DOI: 10.1088/1674-1056/ad6a3c
Hao-Ran Tao, Lei Du, Liang-Liang Guo, Yong Chen, Hai-Feng Zhang, Xiao-Yan Yang, Guo-Liang Xu, Chi Zhang, Zhi-Long Jia, Peng Duan, Guo-Ping Guo
The performance of Nb superconducting quantum devices is predominantly limited by dielectric loss at the metal–air interface, where Nb2O5 is considered the main loss source. Here, we suppress the formation of native oxides by in-situ deposition of a TiN capping layer on the Nb film. With TiN capping layers, no Nb2O5 forms on the surface of the Nb film. The quality factor Qi of the Nb resonator increases from 5.6 × 105 to 7.9 × 105 at low input power and from 6.8 × 106 to 1.1 × 107 at high input power. Furthermore, the TiN capping layer also shows good aging resistance in Nb resonator devices, with no significant performance fluctuations after one month of aging. These findings highlight the effectiveness of TiN capping layers in enhancing the performance and longevity of Nb superconducting quantum devices.
铌超导量子器件的性能主要受限于金属-空气界面的介电损耗，其中 Nb2O5 被认为是主要的损耗源。在这里，我们通过在铌薄膜上原位沉积 TiN 盖层来抑制原生氧化物的形成。有了 TiN 盖层，铌薄膜表面就不会形成 Nb2O5。在低输入功率时，铌谐振器的品质因数 Qi 从 5.6 × 105 提高到 7.9 × 105，在高输入功率时，品质因数 Qi 从 6.8 × 106 提高到 1.1 × 107。此外，TiN 盖层在铌谐振器器件中也表现出良好的抗老化性，老化一个月后性能没有明显波动。这些发现凸显了 TiN 盖层在提高铌超导量子器件的性能和寿命方面的有效性。
{"title":"In-situ deposited anti-aging TiN capping layer for Nb superconducting quantum circuits","authors":"Hao-Ran Tao, Lei Du, Liang-Liang Guo, Yong Chen, Hai-Feng Zhang, Xiao-Yan Yang, Guo-Liang Xu, Chi Zhang, Zhi-Long Jia, Peng Duan, Guo-Ping Guo","doi":"10.1088/1674-1056/ad6a3c","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6a3c","url":null,"abstract":"The performance of Nb superconducting quantum devices is predominantly limited by dielectric loss at the metal–air interface, where Nb<sub>2</sub>O<sub>5</sub> is considered the main loss source. Here, we suppress the formation of native oxides by <italic toggle=\"yes\">in-situ</italic> deposition of a TiN capping layer on the Nb film. With TiN capping layers, no Nb<sub>2</sub>O<sub>5</sub> forms on the surface of the Nb film. The quality factor <italic toggle=\"yes\">Q</italic><sub>i</sub> of the Nb resonator increases from 5.6 × 10<sup>5</sup> to 7.9 × 10<sup>5</sup> at low input power and from 6.8 × 10<sup>6</sup> to 1.1 × 10<sup>7</sup> at high input power. Furthermore, the TiN capping layer also shows good aging resistance in Nb resonator devices, with no significant performance fluctuations after one month of aging. These findings highlight the effectiveness of TiN capping layers in enhancing the performance and longevity of Nb superconducting quantum devices.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"46 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-09-01DOI: 10.1088/1674-1056/ad6b86
Bihu Lv, Jiandong Zhang, Chuang Li
Levitated optomechanical systems represent an excellent candidate platform for force and acceleration sensing. We propose a force-sensing protocol utilizing an optically levitated nanoparticle array. In our scheme, N nanoparticles are trapped in an optical cavity using holographic optical tweezers. An external laser drives the cavity, exciting N cavity modes interacting simultaneously with the N nanoparticles. The optomechanical interaction encodes the information of the force acting on each nanoparticle onto the intracavity photons, which can be detected directly at the output ports of the cavity. Consequently, our protocol enables real-time imaging of a force field.
悬浮光学机械系统是力和加速度传感的绝佳候选平台。我们提出了一种利用光悬浮纳米粒子阵列的力传感协议。在我们的方案中，使用全息光镊将 N 个纳米粒子困在一个光腔中。外部激光器驱动空腔，激发 N 个空腔模式同时与 N 个纳米粒子相互作用。光机械相互作用将作用在每个纳米粒子上的力的信息编码为腔内光子，这些光子可直接在腔的输出端口检测到。因此，我们的方案可以实现力场的实时成像。
{"title":"Imaging a force field via an optically levitated nanoparticle array","authors":"Bihu Lv, Jiandong Zhang, Chuang Li","doi":"10.1088/1674-1056/ad6b86","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6b86","url":null,"abstract":"Levitated optomechanical systems represent an excellent candidate platform for force and acceleration sensing. We propose a force-sensing protocol utilizing an optically levitated nanoparticle array. In our scheme, <italic toggle=\"yes\">N</italic> nanoparticles are trapped in an optical cavity using holographic optical tweezers. An external laser drives the cavity, exciting <italic toggle=\"yes\">N</italic> cavity modes interacting simultaneously with the <italic toggle=\"yes\">N</italic> nanoparticles. The optomechanical interaction encodes the information of the force acting on each nanoparticle onto the intracavity photons, which can be detected directly at the output ports of the cavity. Consequently, our protocol enables real-time imaging of a force field.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"9 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Recent experimental advancements reported a chemical reaction between antimony and nitrogen under high temperature and high pressure, yielding crystalline antimony nitride (Sb3N5) with an orthorhombic structure. Motivated by this statement, we calculate the stability, elastic properties, electronic properties and energy density of the Cmc21 structure for pnictogen nitrides X3N5 (X = P, As, Sb, and Bi) using first-principles calculations combined with particle swarm optimization algorithms. Calculations of formation enthalpies, elastic constants and phonon spectra show that P3N5, As3N5 and Sb3N5 are thermodynamically, mechanically and kinetically stable at 35 GPa, whereas Bi3N5 is mechanically and kinetically stable but thermodynamically unstable. The computed electronic density of states shows strong covalent bonding between the N atoms and the phosphorus group atoms in the four compounds, confirmed by the calculated electronic localization function. We also calculate the energy densities for Sb3N5 and find it to be a potentially high-energy-density material.
{"title":"Theoretical insights into the structures and fundamental properties of pnictogen nitrides","authors":"Jingjing Wang, Panlong Kong, Dingmei Zhang, Defang Gao, Zaifu Jiang, Wei Dai","doi":"10.1088/1674-1056/ad6a07","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6a07","url":null,"abstract":"Recent experimental advancements reported a chemical reaction between antimony and nitrogen under high temperature and high pressure, yielding crystalline antimony nitride (Sb<sub>3</sub>N<sub>5</sub>) with an orthorhombic structure. Motivated by this statement, we calculate the stability, elastic properties, electronic properties and energy density of the <italic toggle=\"yes\">Cmc</italic>2<sub>1</sub> structure for pnictogen nitrides <italic toggle=\"yes\">X</italic><sub>3</sub>N<sub>5</sub> (<italic toggle=\"yes\">X</italic> = P, As, Sb, and Bi) using first-principles calculations combined with particle swarm optimization algorithms. Calculations of formation enthalpies, elastic constants and phonon spectra show that P<sub>3</sub>N<sub>5</sub>, As<sub>3</sub>N<sub>5</sub> and Sb<sub>3</sub>N<sub>5</sub> are thermodynamically, mechanically and kinetically stable at 35 GPa, whereas Bi<sub>3</sub>N<sub>5</sub> is mechanically and kinetically stable but thermodynamically unstable. The computed electronic density of states shows strong covalent bonding between the N atoms and the phosphorus group atoms in the four compounds, confirmed by the calculated electronic localization function. We also calculate the energy densities for Sb<sub>3</sub>N<sub>5</sub> and find it to be a potentially high-energy-density material.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"10 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Scaling up spin qubits in silicon-based quantum dots is one of the pivotal challenges in achieving large-scale semiconductor quantum computation. To satisfy the connectivity requirements and reduce the lithographic complexity, utilizing the qubit array structure and the circuit quantum electrodynamics (cQED) architecture together is expected to be a feasible scaling scheme. A triple-quantum dot (TQD) coupled with a superconducting resonator is regarded as a basic cell to demonstrate this extension scheme. In this article, we investigate a system consisting of a silicon TQD and a high-impedance TiN coplanar waveguide (CPW) resonator. The TQD can couple to the resonator via the right double-quantum dot (RDQD), which reaches the strong coupling regime with a charge–photon coupling strength of g0/(2π) = 175 MHz. Moreover, we illustrate the high tunability of the TQD through the characterization of stability diagrams, quadruple points (QPs), and the quantum cellular automata (QCA) process. Our results contribute to fostering the exploration of silicon-based qubit integration.
{"title":"Coupling and characterization of a Si/SiGe triple quantum dot array with a microwave resonator","authors":"Shun-Li Jiang, Tian-Yi Jiang, Yong-Qiang Xu, Rui Wu, Tian-Yue Hao, Shu-Kun Ye, Ran-Ran Cai, Bao-Chuan Wang, Hai-Ou Li, Gang Cao, Guo-Ping Guo","doi":"10.1088/1674-1056/ad711d","DOIUrl":"https://doi.org/10.1088/1674-1056/ad711d","url":null,"abstract":"Scaling up spin qubits in silicon-based quantum dots is one of the pivotal challenges in achieving large-scale semiconductor quantum computation. To satisfy the connectivity requirements and reduce the lithographic complexity, utilizing the qubit array structure and the circuit quantum electrodynamics (cQED) architecture together is expected to be a feasible scaling scheme. A triple-quantum dot (TQD) coupled with a superconducting resonator is regarded as a basic cell to demonstrate this extension scheme. In this article, we investigate a system consisting of a silicon TQD and a high-impedance TiN coplanar waveguide (CPW) resonator. The TQD can couple to the resonator via the right double-quantum dot (RDQD), which reaches the strong coupling regime with a charge–photon coupling strength of <italic toggle=\"yes\">g</italic><sub>0</sub>/(2<italic toggle=\"yes\">π</italic>) = 175 MHz. Moreover, we illustrate the high tunability of the TQD through the characterization of stability diagrams, quadruple points (QPs), and the quantum cellular automata (QCA) process. Our results contribute to fostering the exploration of silicon-based qubit integration.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"26 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 discovery of nickelate superconductors, including doped infinite-layer (IL) nickelates RNiO2 (R = La, Pr, Nd), layered square-planar nickelate Nd6Ni5O12, and the Ruddlesden–Popper (RP) phase La3Ni2O7, has spurred immense interest in fundamental research and potential applications. Scanning transmission electron microscopy (STEM) has proven crucial for understanding structure–property correlations in these diverse nickelate superconducting systems. In this review, we summarize the key findings from various modes of STEM, elucidating the mechanism of different nickelate superconductors. We also discuss future perspectives on emerging STEM techniques for unraveling the pairing mechanism in the “nickel age” of superconductivity.
{"title":"Probing nickelate superconductors at atomic scale: A STEM review","authors":"Yihan Lei, Yanghe Wang, Jiahao Song, Jinxin Ge, Dirui Wu, Yingli Zhang, Changjian Li","doi":"10.1088/1674-1056/ad6a0d","DOIUrl":"https://doi.org/10.1088/1674-1056/ad6a0d","url":null,"abstract":"The discovery of nickelate superconductors, including doped infinite-layer (IL) nickelates <italic toggle=\"yes\">R</italic>NiO<sub>2</sub> (<italic toggle=\"yes\">R</italic> = La, Pr, Nd), layered square-planar nickelate Nd<sub>6</sub>Ni<sub>5</sub>O<sub>12</sub>, and the Ruddlesden–Popper (RP) phase La<sub>3</sub>Ni<sub>2</sub>O<sub>7</sub>, has spurred immense interest in fundamental research and potential applications. Scanning transmission electron microscopy (STEM) has proven crucial for understanding structure–property correlations in these diverse nickelate superconducting systems. In this review, we summarize the key findings from various modes of STEM, elucidating the mechanism of different nickelate superconductors. We also discuss future perspectives on emerging STEM techniques for unraveling the pairing mechanism in the “nickel age” of superconductivity.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"73 4 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 Sm–Zr–Fe–Co–Ti quinary-alloys with ThMn12 structure has attracted wide attention for ultra-high intrinsic magnetic properties, showing potentiality to be developed into rare-earth permanent magnets. The Ti element in alloys is crucial for phase stability and magnetic properties, and lower Ti content can increase intrinsic magnetic properties but reduce phase stability. In this study, the 1:12 single-phase melt-spun ribbons with low Ti content was successfully prepared using a rapid solidification non-equilibrium method for the Sm1.1Zr0.2Fe9.2Co2.3Ti0.5 quinary-alloy. However, this non-equilibrium ribbon did not achieve good magnetic hardening due to the uneven microstructure and microstrain. Then, annealing was carried out to eliminate micro-strain and homogenize microstructure, therefore, remanence and coercivity were significantly improved even the precipitation of a small amount of α-Fe phase which were not conducive to coercivity. The remanence of 86.1 emu/g and coercivity of 151 kA/m was achieved when annealing at 850 °C for 45 min. After hot pressing, under the action of high temperature and pressure, a small portion of ThMn12 phases in the magnet decompose into Sm-rich phases and α-Fe, while remanence of 4.02 kGs (1 Gs = 10−4 T), and coercivity of 1.12 kOe (1 Oe = 79.5775 A⋅m−1) were still acquired. Our findings can provide reference for exploring practical permanent magnets made of 1:12 type quinary-alloys.
{"title":"Preparation and magnetic hardening of low Ti content (Sm,Zr)(Fe,Co,Ti)12 magnets by rapid solidification non-equilibrium method","authors":"Xing-Feng Zhang, Li-Bin Liu, Yu-Qing Li, Dong-Tao Zhang, Wei-Qiang Liu, Ming Yue","doi":"10.1088/1674-1056/ad58c4","DOIUrl":"https://doi.org/10.1088/1674-1056/ad58c4","url":null,"abstract":"The Sm–Zr–Fe–Co–Ti quinary-alloys with ThMn<sub>12</sub> structure has attracted wide attention for ultra-high intrinsic magnetic properties, showing potentiality to be developed into rare-earth permanent magnets. The Ti element in alloys is crucial for phase stability and magnetic properties, and lower Ti content can increase intrinsic magnetic properties but reduce phase stability. In this study, the 1:12 single-phase melt-spun ribbons with low Ti content was successfully prepared using a rapid solidification non-equilibrium method for the Sm<sub>1.1</sub>Zr<sub>0.2</sub>Fe<sub>9.2</sub>Co<sub>2.3</sub>Ti<sub>0.5</sub> quinary-alloy. However, this non-equilibrium ribbon did not achieve good magnetic hardening due to the uneven microstructure and microstrain. Then, annealing was carried out to eliminate micro-strain and homogenize microstructure, therefore, remanence and coercivity were significantly improved even the precipitation of a small amount of <italic toggle=\"yes\">α</italic>-Fe phase which were not conducive to coercivity. The remanence of 86.1 emu/g and coercivity of 151 kA/m was achieved when annealing at 850 °C for 45 min. After hot pressing, under the action of high temperature and pressure, a small portion of ThMn<sub>12</sub> phases in the magnet decompose into Sm-rich phases and <italic toggle=\"yes\">α</italic>-Fe, while remanence of 4.02 kGs (1 Gs = 10<sup>−4</sup> T), and coercivity of 1.12 kOe (1 Oe = 79.5775 A⋅m<sup>−1</sup>) were still acquired. Our findings can provide reference for exploring practical permanent magnets made of 1:12 type quinary-alloys.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"9 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-09-01DOI: 10.1088/1674-1056/ad5d99
Xinxin Li, Zhen Deng, Yang Jiang, Chunhua Du, Haiqiang Jia, Wenxin Wang, Hong Chen
Quantum confinement is recognized to be an inherent property in low-dimensional structures. Traditionally, it is believed that the carriers trapped within the well cannot escape due to the discrete energy levels. However, our previous research has revealed efficient carrier escape in low-dimensional structures, contradicting this conventional understanding. In this study, we review the energy band structure of quantum wells along the growth direction considering it as a superposition of the bulk material dispersion and quantization energy dispersion resulting from the quantum confinement across the whole Brillouin zone. By accounting for all wave vectors, we obtain a certain distribution of carrier energy at each quantized energy level, giving rise to the energy subbands. These results enable carriers to escape from the well under the influence of an electric field. Additionally, we have compiled a comprehensive summary of various energy band scenarios in quantum well structures relevant to carrier transport. Such a new interpretation holds significant value in deepening our comprehension of low-dimensional energy bands, discovering new physical phenomena, and designing novel devices with superior performance.
{"title":"Quantum confinement of carriers in the type-I quantum wells structure","authors":"Xinxin Li, Zhen Deng, Yang Jiang, Chunhua Du, Haiqiang Jia, Wenxin Wang, Hong Chen","doi":"10.1088/1674-1056/ad5d99","DOIUrl":"https://doi.org/10.1088/1674-1056/ad5d99","url":null,"abstract":"Quantum confinement is recognized to be an inherent property in low-dimensional structures. Traditionally, it is believed that the carriers trapped within the well cannot escape due to the discrete energy levels. However, our previous research has revealed efficient carrier escape in low-dimensional structures, contradicting this conventional understanding. In this study, we review the energy band structure of quantum wells along the growth direction considering it as a superposition of the bulk material dispersion and quantization energy dispersion resulting from the quantum confinement across the whole Brillouin zone. By accounting for all wave vectors, we obtain a certain distribution of carrier energy at each quantized energy level, giving rise to the energy subbands. These results enable carriers to escape from the well under the influence of an electric field. Additionally, we have compiled a comprehensive summary of various energy band scenarios in quantum well structures relevant to carrier transport. Such a new interpretation holds significant value in deepening our comprehension of low-dimensional energy bands, discovering new physical phenomena, and designing novel devices with superior performance.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"42 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-08-31DOI: 10.1088/1674-1056/ad5a75
Tao Xin, 涛 辛, Ke Zhang, 科 张, Jun Li and 俊 李
Quantum enhanced metrology has the potential to go beyond the standard quantum limit and eventually to the ultimate Heisenberg bound. In particular, quantum probes prepared in nonclassical coherent states have recently been recognized as a useful resource for metrology. Hence, there has been considerable interest in constructing magnetic quantum sensors that combine high resolution and high sensitivity. Here, we explore a nanoscale magnetometer with quantum-enhanced sensitivity, based on 123Sb (I = 7/2) nuclear spin doped in silicon, that takes advantage of techniques of spin-squeezing and coherent control. With the optimal squeezed initial state, the magnetic field sensitivity may be expected to approach 6 aT⋅Hz−1/2⋅cm−3/2 and 603 nT⋅Hz−1/2 at the single-spin level. This magnetic sensor may provide a novel sensitive and high-resolution route to microscopic mapping of magnetic fields as well as other applications.
{"title":"A quantum-enhanced magnetometer using a single high-spin nucleus in silicon","authors":"Tao Xin, 涛 辛, Ke Zhang, 科 张, Jun Li and 俊 李","doi":"10.1088/1674-1056/ad5a75","DOIUrl":"https://doi.org/10.1088/1674-1056/ad5a75","url":null,"abstract":"Quantum enhanced metrology has the potential to go beyond the standard quantum limit and eventually to the ultimate Heisenberg bound. In particular, quantum probes prepared in nonclassical coherent states have recently been recognized as a useful resource for metrology. Hence, there has been considerable interest in constructing magnetic quantum sensors that combine high resolution and high sensitivity. Here, we explore a nanoscale magnetometer with quantum-enhanced sensitivity, based on 123Sb (I = 7/2) nuclear spin doped in silicon, that takes advantage of techniques of spin-squeezing and coherent control. With the optimal squeezed initial state, the magnetic field sensitivity may be expected to approach 6 aT⋅Hz−1/2⋅cm−3/2 and 603 nT⋅Hz−1/2 at the single-spin level. This magnetic sensor may provide a novel sensitive and high-resolution route to microscopic mapping of magnetic fields as well as other applications.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"32 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142264453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-08-01DOI: 10.1088/1674-1056/ad59fb
Yan Gu, Zhanpeng Lu
We investigate the topological phase transition in the Su–Schrieffer–Heeger model with the long-range hopping and quasi-periodic modulation. By numerically calculating the real-space winding number, we obtain topological phase diagrams for different disordered structures. These diagrams suggest that topological phase transitions are different by selecting the specific disordered structure. When quasi-periodic modulation is applied to intracell hopping, the resulting disorder induces topological Anderson insulator (TAI) phase with high winding number (W = 2), but the topological states are destroyed as the disorder increases. Conversely, when intercell hoppings are modulated quasi-periodically, both TAI phase and the process of destruction and restoration of topological zero modes can be induced by disorder. These topological states remain robust even under strong disorder conditions. Our work demonstrates that disorder effects do not always disrupt topological states; rather, with a judicious selection of disordered structures, topological properties can be preserved.
{"title":"Different topological phase transitions in the Su–Schrieffer–Heeger model under different disorder structures","authors":"Yan Gu, Zhanpeng Lu","doi":"10.1088/1674-1056/ad59fb","DOIUrl":"https://doi.org/10.1088/1674-1056/ad59fb","url":null,"abstract":"We investigate the topological phase transition in the Su–Schrieffer–Heeger model with the long-range hopping and quasi-periodic modulation. By numerically calculating the real-space winding number, we obtain topological phase diagrams for different disordered structures. These diagrams suggest that topological phase transitions are different by selecting the specific disordered structure. When quasi-periodic modulation is applied to intracell hopping, the resulting disorder induces topological Anderson insulator (TAI) phase with high winding number (<italic toggle=\"yes\">W</italic> = 2), but the topological states are destroyed as the disorder increases. Conversely, when intercell hoppings are modulated quasi-periodically, both TAI phase and the process of destruction and restoration of topological zero modes can be induced by disorder. These topological states remain robust even under strong disorder conditions. Our work demonstrates that disorder effects do not always disrupt topological states; rather, with a judicious selection of disordered structures, topological properties can be preserved.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"38 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-08-01DOI: 10.1088/1674-1056/ad5af1
Jin Wang, Yu Liu, Taikun Wang, Yongkang Xu, Shuanghai Wang, Kun He, Yafeng Deng, Pengfei Yan, Liang He
Heterostructures of van der Waals (vdW) ferromagnetic materials have become a focal point in research of low-dimensional spintronic devices. The current direction in spin valves is commonly perpendicular to the plane (CPP). However, the transport properties of the CPP mode remain largely unexplored. In this work, current-in-plane (CIP) mode and CPP mode for CrTe2 thin films are carefully studied. The temperature-dependent longitudinal resistance transitions from metallic (CIP) to semiconductor behavior (CPP), with the electrical resistivity of CPP increased by five orders of magnitude. More importantly, the transport properties of the CPP can be categorized into a single-gap tunneling-through model with the activation energy (Ea) of ∼ 1.34 meV/gap at 300–150 K, the variable range hopping model with a linear negative magnetoresistance at 150–20 K, and weak localization region with a nonlinear magnetic resistance below 20 K. This study explores the vertical transport in CrTe2 materials for the first time, contributing to understand its unique properties and to pave the way for its potential in spin valve devices.
范德华（vdW）铁磁材料的异质结构已成为低维自旋电子器件研究的焦点。自旋阀中的电流方向通常垂直于平面（CPP）。然而，CPP 模式的传输特性在很大程度上仍未得到探索。在这项工作中，我们仔细研究了 CrTe2 薄膜的面内电流（CIP）模式和 CPP 模式。随温度变化的纵向电阻从金属行为（CIP）转变为半导体行为（CPP），CPP 的电阻率增加了五个数量级。更重要的是，CPP 的传输特性可分为 300-150 K 时活化能 (Ea) 为 1.34 meV/gap 的单间隙隧穿模型、150-20 K 时线性负磁电阻的变程跳变模型以及 20 K 以下非线性磁电阻的弱局域模型。
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