By utilizing the fluctuation exchange approximation method, we perform a study on the superconducting pairing symmetry in a t2g three-orbital model on the square lattice. Although the tight-binding parameters of the model are based on Sr2RuO4, we have systematically studied the evolution of superconducting pairing symmetry with the carrier density and interactions, making our findings relevant to a broader range of material systems. Under a moderate Hund’s coupling, we find that spin fluctuations dominate the superconducting pairing, leading to a prevalent spin-singlet pairing with a dx2–y2-wave symmetry for the carrier density within the range of n = 1.5–4 per site. By reducing the Hund’s coupling, the charge fluctuations are enhanced and play a crucial role in determining the pairing symmetry, leading to a transition of the pairing symmetry from the spin-singlet dx2–y2-wave to the spin-triplet p-wave. Furthermore, we find that the superconducting pairings are orbital dependent. As the carrier density changes from n = 4 to n = 1.5, the active orbitals for superconducting pairing shift from the quasi-two-dimensional orbital dxy to the quasi-one-dimensional orbitals dxz and dyz.
通过利用波动交换近似方法，我们对方形晶格上的 t2g 三轨道模型中的超导配对对称性进行了研究。虽然模型的紧约束参数是基于 Sr2RuO4，但我们系统地研究了超导配对对称性随载流子密度和相互作用的演变，从而使我们的研究结果适用于更广泛的材料系统。我们发现，在适度的亨德耦合下，自旋波动主导着超导配对，导致载流子密度在每个位点 n = 1.5-4 范围内的自旋-小波配对普遍具有 dx2-y2 波对称性。通过降低亨德耦合，电荷波动增强了，并在决定配对对称性方面发挥了关键作用，导致配对对称性从自旋小波 dx2-y2 波过渡到自旋三重 p 波。此外，我们还发现超导配对与轨道有关。当载流子密度从 n = 4 变为 n = 1.5 时，超导配对的有效轨道从准二维轨道 dxy 转向准一维轨道 dxz 和 dyz。
{"title":"Effects of carrier density and interactions on pairing symmetry in a t2g model","authors":"Yun-Xiao Li, Wen-Han Xi, Zhao-Yang Dong, Zi-Jian Yao, Shun-Li Yu, Jian-Xin Li","doi":"10.1088/1674-1056/ad1094","DOIUrl":"https://doi.org/10.1088/1674-1056/ad1094","url":null,"abstract":"By utilizing the fluctuation exchange approximation method, we perform a study on the superconducting pairing symmetry in a t<sub>2g</sub> three-orbital model on the square lattice. Although the tight-binding parameters of the model are based on Sr<sub>2</sub>RuO<sub>4</sub>, we have systematically studied the evolution of superconducting pairing symmetry with the carrier density and interactions, making our findings relevant to a broader range of material systems. Under a moderate Hund’s coupling, we find that spin fluctuations dominate the superconducting pairing, leading to a prevalent spin-singlet pairing with a d<sub>\u0000<italic toggle=\"yes\">x</italic>\u0000<sup>2</sup>–<italic toggle=\"yes\">y</italic>\u0000<sup>2</sup>\u0000</sub>-wave symmetry for the carrier density within the range of <italic toggle=\"yes\">n</italic> = 1.5–4 per site. By reducing the Hund’s coupling, the charge fluctuations are enhanced and play a crucial role in determining the pairing symmetry, leading to a transition of the pairing symmetry from the spin-singlet d<sub>\u0000<italic toggle=\"yes\">x</italic>\u0000<sup>2</sup>–<italic toggle=\"yes\">y</italic>\u0000<sup>2</sup>\u0000</sub>-wave to the spin-triplet p-wave. Furthermore, we find that the superconducting pairings are orbital dependent. As the carrier density changes from <italic toggle=\"yes\">n</italic> = 4 to <italic toggle=\"yes\">n</italic> = 1.5, the active orbitals for superconducting pairing shift from the quasi-two-dimensional orbital d<sub>\u0000<italic toggle=\"yes\">xy</italic>\u0000</sub> to the quasi-one-dimensional orbitals d<sub>\u0000<italic toggle=\"yes\">xz</italic>\u0000</sub> and d<sub>\u0000<italic toggle=\"yes\">yz</italic>\u0000</sub>.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"31 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092085","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 : 2024-01-01DOI: 10.1088/1674-1056/ad0ec3
Yin-Sheng Lv, Pin-Hua Xie, Jin Xu, You-Tao Li, Hua-Rong Zhang
The Fabry–Pérot (FP) resonant cavity is widely used in laser and spectroscopic measurements due to its unique interference transfer function (ITF). In the ideal case of parallel incident light, the ITF of the FP resonant cavity can be expressed by the Airy function. However, in reality, it is difficult to achieve perfect parallelism with collimated beams. In this article, a theoretical model is established for non-parallel light incidence, which assumes that the non-parallel incident light is a cone-shaped beam, and the cone angle is used to quantify the non-parallelism of the beam. The transmittance function of the FP resonant cavity under non-parallel light incidence is derived. The accuracy of the model is experimentally verified. Based on this model, the effects of divergence angle, tilt angle and FP cavity parameters (reflectivity, cavity length) on the ITF are studied. The reasons for the decrease in peak value, broadening and asymmetry of the interference peak under non-parallel light incidence are explained. It is suggested that a fine balance between the interference peak and the collimation effect of the incident light should be considered in the design and application of FP resonant cavities, especially for tilted applications such as angle-scanned spectroscopy. The research results of this article have certain significance for the design and application of FP resonant cavities.
{"title":"Effective transmittance of Fabry–Perot cavity under non-parallel beam incidence","authors":"Yin-Sheng Lv, Pin-Hua Xie, Jin Xu, You-Tao Li, Hua-Rong Zhang","doi":"10.1088/1674-1056/ad0ec3","DOIUrl":"https://doi.org/10.1088/1674-1056/ad0ec3","url":null,"abstract":"The Fabry–Pérot (FP) resonant cavity is widely used in laser and spectroscopic measurements due to its unique interference transfer function (ITF). In the ideal case of parallel incident light, the ITF of the FP resonant cavity can be expressed by the Airy function. However, in reality, it is difficult to achieve perfect parallelism with collimated beams. In this article, a theoretical model is established for non-parallel light incidence, which assumes that the non-parallel incident light is a cone-shaped beam, and the cone angle is used to quantify the non-parallelism of the beam. The transmittance function of the FP resonant cavity under non-parallel light incidence is derived. The accuracy of the model is experimentally verified. Based on this model, the effects of divergence angle, tilt angle and FP cavity parameters (reflectivity, cavity length) on the ITF are studied. The reasons for the decrease in peak value, broadening and asymmetry of the interference peak under non-parallel light incidence are explained. It is suggested that a fine balance between the interference peak and the collimation effect of the incident light should be considered in the design and application of FP resonant cavities, especially for tilted applications such as angle-scanned spectroscopy. The research results of this article have certain significance for the design and application of FP resonant cavities.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"27 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092142","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}
A quantum teleportation network involving multiple users is essential for future quantum internet. So far, controlled quantum teleportation has been demonstrated in a three-user network. However, versatile and controlled quantum teleportation network involving more users is in demand, which satisfies diff erent combinations of users for practical requirements. Here we propose a highly versatile and controlled teleportation network that can switch among various combinations of diff erent users. We use a single continuous-variable six-partite Greenberger–Horne–Zeilinger (GHZ) state to realize such a task by choosing the diff erent measurement and feedback operations. The controlled teleportation network, which includes one sub-network, two sub-networks and three sub-networks, can be realized for diff erent application of user combinations. Furthermore, the coherent feedback control (CFC) can manipulate and improve the teleportation performance. Our approach is flexible, scalable, and would provide a versatile platform for demonstrations of complex quantum communication and quantum computing protocols.
{"title":"Versatile and controlled quantum teleportation network","authors":"Yao-Yao Zhou, Peng-Xian Mei, Yan-Hong Liu, Liang Wu, Yan-Xiang Li, Zhi-Hui Yan, Xiao-Jun Jia","doi":"10.1088/1674-1056/ad1981","DOIUrl":"https://doi.org/10.1088/1674-1056/ad1981","url":null,"abstract":"A quantum teleportation network involving multiple users is essential for future quantum internet. So far, controlled quantum teleportation has been demonstrated in a three-user network. However, versatile and controlled quantum teleportation network involving more users is in demand, which satisfies diff erent combinations of users for practical requirements. Here we propose a highly versatile and controlled teleportation network that can switch among various combinations of diff erent users. We use a single continuous-variable six-partite Greenberger–Horne–Zeilinger (GHZ) state to realize such a task by choosing the diff erent measurement and feedback operations. The controlled teleportation network, which includes one sub-network, two sub-networks and three sub-networks, can be realized for diff erent application of user combinations. Furthermore, the coherent feedback control (CFC) can manipulate and improve the teleportation performance. Our approach is flexible, scalable, and would provide a versatile platform for demonstrations of complex quantum communication and quantum computing protocols.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":" 8","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139143490","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}
We construct a power enhancement cavity to form an optical lattice in an ytterbium optical clock. It is demonstrated that the intra-cavity lattice power can be increased by about 45 times, and the trap depth can be as large as 1400 E r when laser light with a power of only 0.6 W incidents to the lattice cavity. Such high trap depths are the key to accurate evaluation of the lattice-induced light shift with an uncertainty down to ~1×10-18. By probing the ytterbium atoms trapped in the power-enhanced optical lattice, we obtain a 4.3 Hz-linewidth Rabi spectrum, which is then used to feedback to the clock laser for the close loop operation of the optical lattice clock. We evaluate the density shift of the Yb optical lattice clock based on interleaving measurements, which is -0.46(62) mHz. This result is smaller compared to the density shift of our first Yb optical clock without lattice power enhancement cavity mainly due to a larger lattice diameter of 344 μm.
我们构建了一个功率增强腔，用于在镱光时钟中形成光晶格。实验证明，当功率仅为 0.6 W 的激光进入晶格腔时，腔内晶格功率可提高约 45 倍，陷阱深度可达 1400 E r。如此高的阱深是精确评估晶格诱导光偏移的关键，其不确定性可低至 ~1×10-18。通过探测被困在功率增强光晶格中的镱原子，我们获得了 4.3 Hz 线宽的拉比光谱，然后将其反馈给时钟激光器，用于光晶格时钟的闭环操作。我们根据交错测量结果评估了掺镱光晶格时钟的密度偏移，结果为-0.46(62) mHz。与我们第一个不带晶格功率增强腔的掺镱光学时钟的密度偏移相比，这一结果较小，这主要是由于晶格直径更大（344 μm）。
{"title":"An Yb optical clock with a lattice power enhancement cavity","authors":"Chunyun Wang, Yuan Yao, Haosen Shi, Hongfu Yu, Longsheng Ma, Yanyi Jiang","doi":"10.1088/1674-1056/ad1986","DOIUrl":"https://doi.org/10.1088/1674-1056/ad1986","url":null,"abstract":"We construct a power enhancement cavity to form an optical lattice in an ytterbium optical clock. It is demonstrated that the intra-cavity lattice power can be increased by about 45 times, and the trap depth can be as large as 1400 E r when laser light with a power of only 0.6 W incidents to the lattice cavity. Such high trap depths are the key to accurate evaluation of the lattice-induced light shift with an uncertainty down to ~1×10-18. By probing the ytterbium atoms trapped in the power-enhanced optical lattice, we obtain a 4.3 Hz-linewidth Rabi spectrum, which is then used to feedback to the clock laser for the close loop operation of the optical lattice clock. We evaluate the density shift of the Yb optical lattice clock based on interleaving measurements, which is -0.46(62) mHz. This result is smaller compared to the density shift of our first Yb optical clock without lattice power enhancement cavity mainly due to a larger lattice diameter of 344 μm.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"61 3","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139146531","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 : 2023-12-29DOI: 10.1088/1674-1056/ad1983
Hao Kuang, Junxiao Yu, Jie Chen, H. E. Elsayed-Ali, Runze Li, Peter M. Rentzepis
With the integration of ultrafast reflectivity and polarimetry probes, we observed carrier relaxation and spin dynamics induced by ultrafast laser excitation of Ni (111) single crystals. The carrier relaxation time within the linear excitation range reveals that the electron-phonon coupling and the dissipation of photon energy into the bulk of the crystal take tens of picoseconds. On the other hand, the observed spin dynamics indicate a longer time of about 120 ps. To further understand how the lattice degree of freedom is coupled with those dynamics, it may further require the integration of an ultrafast diffraction probe.
{"title":"Ultrafast magneto-optical dynamics in Nickel (111) single crystal studied by the integration of ultrafast reflectivity and polarimetry probes","authors":"Hao Kuang, Junxiao Yu, Jie Chen, H. E. Elsayed-Ali, Runze Li, Peter M. Rentzepis","doi":"10.1088/1674-1056/ad1983","DOIUrl":"https://doi.org/10.1088/1674-1056/ad1983","url":null,"abstract":"With the integration of ultrafast reflectivity and polarimetry probes, we observed carrier relaxation and spin dynamics induced by ultrafast laser excitation of Ni (111) single crystals. The carrier relaxation time within the linear excitation range reveals that the electron-phonon coupling and the dissipation of photon energy into the bulk of the crystal take tens of picoseconds. On the other hand, the observed spin dynamics indicate a longer time of about 120 ps. To further understand how the lattice degree of freedom is coupled with those dynamics, it may further require the integration of an ultrafast diffraction probe.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":" 46","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139142431","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 : 2023-12-28DOI: 10.1088/1674-1056/ad1926
Tao Cheng, Run-Sheng Zhao, Shuang Wang, Rui Wang, Hong-Yang Ma
We design a new hybrid quantum-classical convolutional neural network (HQCCNN) model based on parameter quantum circuits. In this model, we use parameterized quantum circuits (PQC) to redesign the convolutional layer in classical convolutional neural networks (CNN), forming a new quantum convolutional layer to achieve unitary transformation of quantum states, enabling the model to more accurately extract hidden information from images. At the same time, we combine the classical fully connected layer with PQC to form a new hybrid quantum-classical fully connected layer to further improve the accuracy of classification. Finally, we used the MNIST dataset to test the potential of HQCCNN. The results indicate that HQCCNN has good performance in solving classification problems. In binary classification tasks, the classification accuracy of numbers 5 and 7 is as high as 99.71%. And in multivariate classification, the accuracy rate also reached 98.51%. Finally, we compare the performance of HQCCNN with other models and find that HQCCNN has better classification performance and convergence speed.
{"title":"Analysis of Learnability of a Novel Hybrid Quantum-Classical Convolutional Neural Network in Image Classification","authors":"Tao Cheng, Run-Sheng Zhao, Shuang Wang, Rui Wang, Hong-Yang Ma","doi":"10.1088/1674-1056/ad1926","DOIUrl":"https://doi.org/10.1088/1674-1056/ad1926","url":null,"abstract":"We design a new hybrid quantum-classical convolutional neural network (HQCCNN) model based on parameter quantum circuits. In this model, we use parameterized quantum circuits (PQC) to redesign the convolutional layer in classical convolutional neural networks (CNN), forming a new quantum convolutional layer to achieve unitary transformation of quantum states, enabling the model to more accurately extract hidden information from images. At the same time, we combine the classical fully connected layer with PQC to form a new hybrid quantum-classical fully connected layer to further improve the accuracy of classification. Finally, we used the MNIST dataset to test the potential of HQCCNN. The results indicate that HQCCNN has good performance in solving classification problems. In binary classification tasks, the classification accuracy of numbers 5 and 7 is as high as 99.71%. And in multivariate classification, the accuracy rate also reached 98.51%. Finally, we compare the performance of HQCCNN with other models and find that HQCCNN has better classification performance and convergence speed.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"5 14","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139148739","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 : 2023-12-28DOI: 10.1088/1674-1056/ad1927
Ling-ling Xing, Huan Yang, Gang Zhang, Min Kong
Einstein-Podolsky-Rosen (EPR) steering is one of nontrivial quantum nonlocalities and characteristics in the non-classical world. The directivity (or asymmetry) is a fascinating trait of the EPR steering, and it is different from other quantum nonlocalities. Here, considering the strategy in which two atoms compose a two-qubit X state, and the two atoms are owned by Alice and Bob, respectively. The atom of Alice suffers from a reservoir, and the atom of Bob couples with a bit flip channel. The influences of auxiliary qubits on the EPR steering and its directions are revealed by means of entropy uncertainty relation. The results indicate that the EPR steering declines with growing time t when adding less auxiliary qubits. The EPR steering behaves as damped oscillation when introducing more auxiliary qubits in the strong coupling regime. In the weak coupling regime, the EPR steering monotonously decreases as t increases when coupling auxiliary qubits. The increases of auxiliary qubits are responsible for the fact that the steerability from Alice to Bob (or from Bob to Alice) can be more effectively revealed. Notably, the introductions of more auxiliary qubits can change the situation that the steerability from Alice to Bob is certain into the situation that the steerability from Bob to Alice is certain.
爱因斯坦-波多尔斯基-罗森（EPR）转向是非经典世界中的一种量子非局域性和特征。方向性（或不对称性）是 EPR 转向的一个迷人特征，它不同于其他量子非局域。在此，我们考虑这样一种策略：两个原子组成一个双量子比特 X 态，这两个原子分别归爱丽丝和鲍勃所有。爱丽丝的原子受到储层的影响，而鲍勃的原子则与比特翻转通道耦合。通过熵不确定性关系揭示了辅助量子比特对 EPR 转向及其方向的影响。结果表明，当添加的辅助量子比特越少，EPR转向就会随着时间 t 的增长而减小。在强耦合机制下，当引入更多辅助量子比特时，EPR转向表现为阻尼振荡。在弱耦合机制中，当耦合辅助量子比特时，EPR 转向随 t 的增大而单调减小。辅助量子位增加的原因是，从爱丽丝到鲍勃（或从鲍勃到爱丽丝）的可转向性可以更有效地揭示出来。值得注意的是，引入更多的辅助量子位可以将从爱丽丝到鲍勃的可转向性确定的情况改变为从鲍勃到爱丽丝的可转向性确定的情况。
{"title":"Ascertaining the influences of auxiliary qubits on the Einstein-Podolsky-Rosen steering and its directions","authors":"Ling-ling Xing, Huan Yang, Gang Zhang, Min Kong","doi":"10.1088/1674-1056/ad1927","DOIUrl":"https://doi.org/10.1088/1674-1056/ad1927","url":null,"abstract":"Einstein-Podolsky-Rosen (EPR) steering is one of nontrivial quantum nonlocalities and characteristics in the non-classical world. The directivity (or asymmetry) is a fascinating trait of the EPR steering, and it is different from other quantum nonlocalities. Here, considering the strategy in which two atoms compose a two-qubit X state, and the two atoms are owned by Alice and Bob, respectively. The atom of Alice suffers from a reservoir, and the atom of Bob couples with a bit flip channel. The influences of auxiliary qubits on the EPR steering and its directions are revealed by means of entropy uncertainty relation. The results indicate that the EPR steering declines with growing time t when adding less auxiliary qubits. The EPR steering behaves as damped oscillation when introducing more auxiliary qubits in the strong coupling regime. In the weak coupling regime, the EPR steering monotonously decreases as t increases when coupling auxiliary qubits. The increases of auxiliary qubits are responsible for the fact that the steerability from Alice to Bob (or from Bob to Alice) can be more effectively revealed. Notably, the introductions of more auxiliary qubits can change the situation that the steerability from Alice to Bob is certain into the situation that the steerability from Bob to Alice is certain.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"59 14","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139150746","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 : 2023-12-26DOI: 10.1088/1674-1056/ad18a9
Zongli Sun, Yanshuang Kang, Yanmei Kang
Combining the mean field Pozhar-Gubbins (PG) theory and the weighted density approximation, a novel method for the local thermal conductivity of inhomogeneous fluids is proposed. The correlation effect that is beyond the mean field treatment is taken into account by the simulation-based empirical correlations. The application of this method to confined argon in slit pore shows that its prediction agrees well with the simulation results, and that it performs better than the original PG theory as well as the local averaged density model (LADM). In its further application to the nano-fluidic films, the influences of fluid parameters and pore parameters on the thermal conductivity are calculated and investigated. It is found that both the local thermal conductivity and the overall thermal conductivity can be significantly modulated by these parameters. Specifically, in the supercritical states, the thermal conductivity of the confined fluid shows positive correlation to the bulk density as well as the temperature. However, when the bulk density is small, the thermal conductivity exhibits a decrease-increase transition as the temperature is increased. This is also the case when the temperature is low. In fact, the decrease-increase transition in both cases arises from the capillary condensation in the pore. Furthermore, smaller pore width and/or stronger adsorption potential can raise the critical temperature for condensation, and then are beneficial to the enhancement of the thermal conductivity. These modulation behaviors of the local thermal conductivity lead immediately to the significant difference of the overall thermal conductivity in different phase regions.
{"title":"Investigation on the local thermal conductivity of inhomogeneous nano-fluidic films: a DFT perspective","authors":"Zongli Sun, Yanshuang Kang, Yanmei Kang","doi":"10.1088/1674-1056/ad18a9","DOIUrl":"https://doi.org/10.1088/1674-1056/ad18a9","url":null,"abstract":"Combining the mean field Pozhar-Gubbins (PG) theory and the weighted density approximation, a novel method for the local thermal conductivity of inhomogeneous fluids is proposed. The correlation effect that is beyond the mean field treatment is taken into account by the simulation-based empirical correlations. The application of this method to confined argon in slit pore shows that its prediction agrees well with the simulation results, and that it performs better than the original PG theory as well as the local averaged density model (LADM). In its further application to the nano-fluidic films, the influences of fluid parameters and pore parameters on the thermal conductivity are calculated and investigated. It is found that both the local thermal conductivity and the overall thermal conductivity can be significantly modulated by these parameters. Specifically, in the supercritical states, the thermal conductivity of the confined fluid shows positive correlation to the bulk density as well as the temperature. However, when the bulk density is small, the thermal conductivity exhibits a decrease-increase transition as the temperature is increased. This is also the case when the temperature is low. In fact, the decrease-increase transition in both cases arises from the capillary condensation in the pore. Furthermore, smaller pore width and/or stronger adsorption potential can raise the critical temperature for condensation, and then are beneficial to the enhancement of the thermal conductivity. These modulation behaviors of the local thermal conductivity lead immediately to the significant difference of the overall thermal conductivity in different phase regions.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"14 8","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139156639","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 : 2023-12-26DOI: 10.1088/1674-1056/ad18aa
Zi Wang, Xin Peng, ShengNan Zhang, Yahui Su, Shaodong Lai, Xuan Zhou, Chun-Shian Wu, Tingyu Zhou, Hangdong Wang, Jinhu Yang, Bin Chen, Huifei Zhai, Quansheng Wu, J. Du, Zhiwei Jiao, Minghu Fang
Intercalated transition metal dichalcogenides (TMDCs) attract much attention due to their rich properties and potential applications. In this Letter, we grew successfully high-quality V$_{1/3}$TaS$_{2}$ crystals by a vapor transport method. We measured the magnetization, longitudinal resistivity $rho_{xx}$($T, H$), Hall resistivity $rho_{xy}$($T, H$), as well as performed calculations of the electronic band structure. It was found that V$_{1/3}$TaS$_{2}$ is an A-type antiferromagnet with the Neel temperature $T_{N}$ = 6.20 K, and exhibits a negative magnetoresistance (MR) near $T_{N}$. Both band structure calculations and Hall resistivity measurements demonstrate it to be a magnetic semimetal.
夹杂过渡金属二卤化物（TMDCs）因其丰富的特性和潜在的应用而备受关注。在这封信中，我们采用气相传输方法成功地生长出了高质量的 V$_{1/3}$TaS$_{2}$ 晶体。我们测量了晶体的磁化率、纵向电阻率 $rrho_{xx}$($T，H$)、霍尔电阻率 $rrho_{xy}$($T，H$)，并对其电子能带结构进行了计算。研究发现，V$_{1/3}$TaS$_{2}$ 是一种 Neel 温度为 $T_{N}$ = 6.20 K 的 A 型反铁磁体，并且在 $T_{N}$ 附近表现出负磁阻 (MR)。带状结构计算和霍尔电阻率测量都证明它是一种磁性半金属。
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Pub Date : 2023-12-25DOI: 10.1088/1674-1056/ad188f
Jun Cheng, Liang Sun, Yike Zhang, Tongzhou Ji, Rongxing Cao, B. Miao, Yonggang Zhao, Haifeng Ding
Recent theory and experiments show that artificial magnetic skyrmions can be stabilized at room temperature without the need of the external magnetic field, casting strong potentials for the device applications. In this work, we study the electric field manipulation of artificial magnetic skyrmions imprinted by Co disks on CoPt multilayers utilizing the micromagnetic simulations. We find that the reversible annihilation and creation of skyrmions can be realized with the electric field via the strain mediated magnetoelastic coupling. In addition, we also demonstrate controllable manipulation of individual skyrmion, which opens a new platform for constructing magnetic-field-free and low-energy-dissipation skyrmion-based media.
最近的理论和实验表明，人造磁性天幕可以在室温下稳定而无需外部磁场，这为器件应用提供了强大的潜力。在这项工作中，我们利用微磁模拟研究了 CoPt 多层板上由 Co 磁盘压印的人工磁性天幕的电场操纵。我们发现，通过应变介导的磁弹性耦合，可以在电场作用下实现天磁的可逆湮灭和产生。此外，我们还展示了对单个天融子的可控操纵，这为构建无磁场和低能耗天融子介质开辟了一个新平台。
{"title":"Creation and annihilation of artificial magnetic skyrmions with the electric field","authors":"Jun Cheng, Liang Sun, Yike Zhang, Tongzhou Ji, Rongxing Cao, B. Miao, Yonggang Zhao, Haifeng Ding","doi":"10.1088/1674-1056/ad188f","DOIUrl":"https://doi.org/10.1088/1674-1056/ad188f","url":null,"abstract":"Recent theory and experiments show that artificial magnetic skyrmions can be stabilized at room temperature without the need of the external magnetic field, casting strong potentials for the device applications. In this work, we study the electric field manipulation of artificial magnetic skyrmions imprinted by Co disks on CoPt multilayers utilizing the micromagnetic simulations. We find that the reversible annihilation and creation of skyrmions can be realized with the electric field via the strain mediated magnetoelastic coupling. In addition, we also demonstrate controllable manipulation of individual skyrmion, which opens a new platform for constructing magnetic-field-free and low-energy-dissipation skyrmion-based media.","PeriodicalId":10253,"journal":{"name":"Chinese Physics B","volume":"9 5","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139158668","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}
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