Pub Date : 2023-12-01DOI: 10.1088/0256-307x/41/1/016302
Menglin Li, M. A. Shakoori, Ruipeng Wang, Haipeng Li
In this paper, molecular dynamics simulation is used to calculate the interfacial thermal resistance (ITR) of the graphene/carbon nanotubes/hexagonal boron nitride (Gr/CNTs/hBN) sandwich heterostructure, of which vertically aligned carbon nanotube (VACNT) arrays is covalently bonded to graphene and hexagonal boron nitride layers. We found that the ITR of the Gr/VACNT/hBN sandwich heterostructure is 1-2 orders of magnitude smaller than the ITR of the Gr/hBN Van der Waals heterostructure with the same plane size. It is observed that the covalent bonding effectively enhances the phonon coupling between Gr and hBN layers, resulting in an increase in the overlap factor of phonon density of state between Gr and hBN, thus reducing the ITR of Gr and hBN. In addition, the chirality, size (diameter and length) and packing density of sandwich-layer VACNT have an important influence on the ITR of the heterostructure. Under the same diameter and length of CNT, the ITR of the sandwich heterostructure with armchair-shaped VACNT is higher than that of the sandwich heterostructure with zigzag-shaped VACNT, due to the different chemical bonding of chiral CNT with Gr and hBN. When the armchairshaped CNT diameter increases or the length decreases, the ITR of the sandwich heterostructure tends to decrease. Moreover, the increase in the packing density of VACNT has also led to a continuous decrease in the ITR of the sandwich heterostructure, attributed to the extremely high intrinsic thermal conductivity of CNT and the increase of out-ofplane heat transfer channels. This work will help to understand the mechanism for ITR for multi-layer vertical heterostructures, and provide theoretical guidance for a new strategy to regulate the inter-layer thermal resistance of heterostructures by optimizing the design of sandwich layer thermal interface materials.
{"title":"Phonon thermal transport at the interfaces of graphene/vertically aligned carbon nanotubes /hexagonal boron nitride sandwich heterostructure","authors":"Menglin Li, M. A. Shakoori, Ruipeng Wang, Haipeng Li","doi":"10.1088/0256-307x/41/1/016302","DOIUrl":"https://doi.org/10.1088/0256-307x/41/1/016302","url":null,"abstract":"\u0000 In this paper, molecular dynamics simulation is used to calculate the interfacial thermal resistance (ITR) of the graphene/carbon nanotubes/hexagonal boron nitride (Gr/CNTs/hBN) sandwich heterostructure, of which vertically aligned carbon nanotube (VACNT) arrays is covalently bonded to graphene and hexagonal boron nitride layers. We found that the ITR of the Gr/VACNT/hBN sandwich heterostructure is 1-2 orders of magnitude smaller than the ITR of the Gr/hBN Van der Waals heterostructure with the same plane size. It is observed that the covalent bonding effectively enhances the phonon coupling between Gr and hBN layers, resulting in an increase in the overlap factor of phonon density of state between Gr and hBN, thus reducing the ITR of Gr and hBN. In addition, the chirality, size (diameter and length) and packing density of sandwich-layer VACNT have an important influence on the ITR of the heterostructure. Under the same diameter and length of CNT, the ITR of the sandwich heterostructure with armchair-shaped VACNT is higher than that of the sandwich heterostructure with zigzag-shaped VACNT, due to the different chemical bonding of chiral CNT with Gr and hBN. When the armchairshaped CNT diameter increases or the length decreases, the ITR of the sandwich heterostructure tends to decrease. Moreover, the increase in the packing density of VACNT has also led to a continuous decrease in the ITR of the sandwich heterostructure, attributed to the extremely high intrinsic thermal conductivity of CNT and the increase of out-ofplane heat transfer channels. This work will help to understand the mechanism for ITR for multi-layer vertical heterostructures, and provide theoretical guidance for a new strategy to regulate the inter-layer thermal resistance of heterostructures by optimizing the design of sandwich layer thermal interface materials.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":"33 S123","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138623219","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}
Pub Date : 2023-12-01DOI: 10.1088/0256-307x/40/12/126101
Ao Zhang, Ke Deng, Jieming Sheng, Pengfei Liu, Shiv Kumar, Kenya Shimada, Zhicheng Jiang, Zhengtai Liu, Dawei Shen, Jiayu Li, Jun Ren, Le Wang, Liang Zhou, Yoshihisa Ishikawa, Takashi Ohhara, Qiang Zhang, Garry McIntyre, Dehong Yu, Enke Liu, Liusuo Wu, Chaoyu Chen, Qihang Liu
In a Dirac semimetal, the massless Dirac fermion has zero chirality, leading to surface states connected adiabatically to a topologically trivial surface state as well as vanishing anomalous Hall effect. Recently, it is predicted that in the nonrelativistic limit of certain collinear antiferromagnets, there exists a type of chiral “Dirac-like” fermion, whose dispersion manifests four-fold degenerate crossing points formed by spin-degenerate linear bands, with topologically protected Fermi arcs. Such an unconventional chiral fermion, protected by a hidden SU(2) symmetry in the hierarchy of an enhanced crystallographic group, namely spin space group, is not experimentally verified yet. Here, by angle-resolved photoemission spectroscopy measurements, we reveal the surface origin of the electron pocket at the Fermi surface in collinear antiferromagnet CoNb3S6. Combining with neutron diffraction and first-principles calculations, we suggest a multidomain collinear antiferromagnetic configuration, rendering the the existence of the Fermi-arc surface states induced by chiral Dirac-like fermions. Our work provides spectral evidence of the chiral Dirac-like fermion caused by particular spin symmetry in CoNb3S6, paving an avenue for exploring new emergent phenomena in antiferromagnets with unconventional quasiparticle excitations.
{"title":"Chiral Dirac Fermion in a Collinear Antiferromagnet","authors":"Ao Zhang, Ke Deng, Jieming Sheng, Pengfei Liu, Shiv Kumar, Kenya Shimada, Zhicheng Jiang, Zhengtai Liu, Dawei Shen, Jiayu Li, Jun Ren, Le Wang, Liang Zhou, Yoshihisa Ishikawa, Takashi Ohhara, Qiang Zhang, Garry McIntyre, Dehong Yu, Enke Liu, Liusuo Wu, Chaoyu Chen, Qihang Liu","doi":"10.1088/0256-307x/40/12/126101","DOIUrl":"https://doi.org/10.1088/0256-307x/40/12/126101","url":null,"abstract":"In a Dirac semimetal, the massless Dirac fermion has zero chirality, leading to surface states connected adiabatically to a topologically trivial surface state as well as vanishing anomalous Hall effect. Recently, it is predicted that in the nonrelativistic limit of certain collinear antiferromagnets, there exists a type of chiral “Dirac-like” fermion, whose dispersion manifests four-fold degenerate crossing points formed by spin-degenerate linear bands, with topologically protected Fermi arcs. Such an unconventional chiral fermion, protected by a hidden <italic toggle=\"yes\">SU</italic>(2) symmetry in the hierarchy of an enhanced crystallographic group, namely spin space group, is not experimentally verified yet. Here, by angle-resolved photoemission spectroscopy measurements, we reveal the surface origin of the electron pocket at the Fermi surface in collinear antiferromagnet CoNb<sub>3</sub>S<sub>6</sub>. Combining with neutron diffraction and first-principles calculations, we suggest a multidomain collinear antiferromagnetic configuration, rendering the the existence of the Fermi-arc surface states induced by chiral Dirac-like fermions. Our work provides spectral evidence of the chiral Dirac-like fermion caused by particular spin symmetry in CoNb<sub>3</sub>S<sub>6</sub>, paving an avenue for exploring new emergent phenomena in antiferromagnets with unconventional quasiparticle excitations.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":"87 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139055451","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}
Pub Date : 2023-12-01DOI: 10.1088/0256-307x/40/12/125201
Hui Li, Yan-Lin Fu, Ji-Quan Li, Zheng-Xiong Wang
Machine learning opens up new possibilities for research of plasma confinement. Specifically, models constructed using machine learning algorithms may effectively simplify the simulation process. Previous first-principles simulations could provide physics-based transport information, but not fast enough for real-time applications or plasma control. To address this issue, this study proposes SExFC, a surrogate model of the Gyro-Landau Extended Fluid Code (ExFC). As an extended version of our previous model ExFC-NN, SExFC can capture more features of transport driven by the ion temperature gradient mode and trapped electron mode, using an extended database initially generated with ExFC simulations. In addition to predicting the dominant instability, radially averaged fluxes and radial profiles of fluxes, the well-trained SExFC may also be suitable for physics-based rapid predictions that can be considered in real-time plasma control systems in the future.
{"title":"Simulation Prediction of Heat Transport with Machine Learning in Tokamak Plasmas","authors":"Hui Li, Yan-Lin Fu, Ji-Quan Li, Zheng-Xiong Wang","doi":"10.1088/0256-307x/40/12/125201","DOIUrl":"https://doi.org/10.1088/0256-307x/40/12/125201","url":null,"abstract":"Machine learning opens up new possibilities for research of plasma confinement. Specifically, models constructed using machine learning algorithms may effectively simplify the simulation process. Previous first-principles simulations could provide physics-based transport information, but not fast enough for real-time applications or plasma control. To address this issue, this study proposes SExFC, a surrogate model of the Gyro-Landau Extended Fluid Code (ExFC). As an extended version of our previous model ExFC-NN, SExFC can capture more features of transport driven by the ion temperature gradient mode and trapped electron mode, using an extended database initially generated with ExFC simulations. In addition to predicting the dominant instability, radially averaged fluxes and radial profiles of fluxes, the well-trained SExFC may also be suitable for physics-based rapid predictions that can be considered in real-time plasma control systems in the future.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":"24 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139055454","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}
Pub Date : 2023-12-01DOI: 10.1088/0256-307x/40/12/120202
Dinghao Zhu, Xiaodong Zhu
The b-family fifth-order Camassa–Holm model is a nontrivial extension of the celebrated Camassa–Holm model. This work investigates single-pseudo and multi-pseudo peakon solutions of this model via analytical calculations and numerical simulations. Some intriguing phenomena of multi-pseudo peakon which do not appear in the classical Camassa–Holm model interactions are observed, such as two-pseudo peakon collapses, three-pseudo peakon resonance, and multi-pseudo peakon inelastic collisions. The present work will inspire further studies on the higher-dimensional integrable Camassa–Holm systems which may have high value in investigating the related higher-dimensional physical problems.
{"title":"Multi-Pseudo Peakons in the b-Family Fifth-Order Camassa–Holm Model","authors":"Dinghao Zhu, Xiaodong Zhu","doi":"10.1088/0256-307x/40/12/120202","DOIUrl":"https://doi.org/10.1088/0256-307x/40/12/120202","url":null,"abstract":"The <italic toggle=\"yes\">b</italic>-family fifth-order Camassa–Holm model is a nontrivial extension of the celebrated Camassa–Holm model. This work investigates single-pseudo and multi-pseudo peakon solutions of this model via analytical calculations and numerical simulations. Some intriguing phenomena of multi-pseudo peakon which do not appear in the classical Camassa–Holm model interactions are observed, such as two-pseudo peakon collapses, three-pseudo peakon resonance, and multi-pseudo peakon inelastic collisions. The present work will inspire further studies on the higher-dimensional integrable Camassa–Holm systems which may have high value in investigating the related higher-dimensional physical problems.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":"26 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139093812","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}
Pub Date : 2023-12-01DOI: 10.1088/0256-307x/40/12/124204
Xin Zhang, Houhui Yi, Yanli Yao, Shubin Wang, Lingxian Shi
The interactions of optical solitons can be used to develop photonic information processing devices such as all optical switches and all optical logic gates. It is the key to achieving high-speed, high-capacity all optical networks and optical computers, and has important academic value. This paper is based on the coupled nonlinear Schrödinger equations to study the properties of all optical switches of optical solitons in birefringent fibers. Through the researches, it was found that different initial conditions can achieve all optical switching function, and the influence of different physical parameters of birefringent fibers on all optical soliton switching was studied. The relevant conclusions are conducive to achieving the all-optical switching function of optical solitons in birefringent fibers, providing useful guidance for the widespread application of optical soliton all-optical switches in birefringent fibers in fiber communications.
{"title":"All optical switches for optical soliton interactions in a birefringent fiber","authors":"Xin Zhang, Houhui Yi, Yanli Yao, Shubin Wang, Lingxian Shi","doi":"10.1088/0256-307x/40/12/124204","DOIUrl":"https://doi.org/10.1088/0256-307x/40/12/124204","url":null,"abstract":"\u0000 The interactions of optical solitons can be used to develop photonic information processing devices such as all optical switches and all optical logic gates. It is the key to achieving high-speed, high-capacity all optical networks and optical computers, and has important academic value. This paper is based on the coupled nonlinear Schrödinger equations to study the properties of all optical switches of optical solitons in birefringent fibers. Through the researches, it was found that different initial conditions can achieve all optical switching function, and the influence of different physical parameters of birefringent fibers on all optical soliton switching was studied. The relevant conclusions are conducive to achieving the all-optical switching function of optical solitons in birefringent fibers, providing useful guidance for the widespread application of optical soliton all-optical switches in birefringent fibers in fiber communications.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":" 13","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138615277","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}
Pub Date : 2023-12-01DOI: 10.1088/0256-307x/40/12/120201
Lu Zhao, Lei Wang
We introduce a method for computing the Helmholtz free energy using the flow matching technique. Unlike previous work that utilized flow-based models for variational free energy calculations, this method provides bounds for free energy estimation based on targeted free energy perturbation by performing calculations on samples from both ends of the mapping. We demonstrate applications of the present method by estimating the free energy of a classical Coulomb gas in a harmonic trap.
{"title":"Bounding Free Energy Difference with Flow Matching","authors":"Lu Zhao, Lei Wang","doi":"10.1088/0256-307x/40/12/120201","DOIUrl":"https://doi.org/10.1088/0256-307x/40/12/120201","url":null,"abstract":"We introduce a method for computing the Helmholtz free energy using the flow matching technique. Unlike previous work that utilized flow-based models for variational free energy calculations, this method provides bounds for free energy estimation based on targeted free energy perturbation by performing calculations on samples from both ends of the mapping. We demonstrate applications of the present method by estimating the free energy of a classical Coulomb gas in a harmonic trap.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":"11 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139055453","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}
Pub Date : 2023-12-01DOI: 10.1088/0256-307x/40/12/127301
Haoran Wei, Mengmeng Wu, Renfei Wang, Mingcheng He, Hiroki Ikegami, Yang Liu, Zhi Gang Cheng
Electron systems in low dimensions are enriched with many superior properties for both fundamental research and technical developments. Wide tunability of electron density, high mobility of motion, and feasible controllability in microscales are the most prominent advantages that researchers strive for. Nevertheless, it is always difficult to fulfill all in one solid-state system. Two-dimensional electron systems (2DESs) floating above the superfluid helium surfaces are thought to meet these three requirements simultaneously, ensured by the atomic smoothness of surfaces and the electric neutrality of helium. Here we report our recent work in preparing, characterizing, and manipulating 2DESs on superfluid helium. We realized a tunability of electron density over one order of magnitude and tuned their transport properties by varying electron distribution and measurement frequency. The work we engage in is crucial for advancing research in many-body physics and for development of single-electron quantum devices rooted in these electron systems.
{"title":"Realizations, Characterizations, and Manipulations of Two-Dimensional Electron Systems Floating above Superfluid Helium Surfaces","authors":"Haoran Wei, Mengmeng Wu, Renfei Wang, Mingcheng He, Hiroki Ikegami, Yang Liu, Zhi Gang Cheng","doi":"10.1088/0256-307x/40/12/127301","DOIUrl":"https://doi.org/10.1088/0256-307x/40/12/127301","url":null,"abstract":"Electron systems in low dimensions are enriched with many superior properties for both fundamental research and technical developments. Wide tunability of electron density, high mobility of motion, and feasible controllability in microscales are the most prominent advantages that researchers strive for. Nevertheless, it is always difficult to fulfill all in one solid-state system. Two-dimensional electron systems (2DESs) floating above the superfluid helium surfaces are thought to meet these three requirements simultaneously, ensured by the atomic smoothness of surfaces and the electric neutrality of helium. Here we report our recent work in preparing, characterizing, and manipulating 2DESs on superfluid helium. We realized a tunability of electron density over one order of magnitude and tuned their transport properties by varying electron distribution and measurement frequency. The work we engage in is crucial for advancing research in many-body physics and for development of single-electron quantum devices rooted in these electron systems.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":"205 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139055242","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}
Mn3Sn2 has been proposed as an ideal material for magnetic refrigeration. It undergoes two successive ferromagnetic transitions (TC1 = 262 K and TC2 = 227 K) and one antiferromagnetic transition (TN = 192 K). Herein we report, for the first time, the preparation of single crystals of Mn3Sn2 from Bi flux. The resultant anisotropic magnetic properties and magnetocaloric effect are investigated along the three principal crystallographic directions of the crystal. Significant anisotropy of magnetic susceptibility and multiple field-induced metamagnetic transitions were found at low fields, whereas the magnetocaloric effect was found to be almost isotropic and larger than that of the polycrystalline one. The maximum magnetic entropy change amounts to −ΔSM = 4.01 J⋅kg−1⋅K−1 near TC1 under a magnetic field change of μ0ΔH = 5 T along the c-axis, with the corresponding refrigerant capacity of 1750 mJ⋅cm−3. Combined with a much wider cooling temperature span (∼ 80 K), our results demonstrate Mn3Sn2 single crystal to be an attractive candidate working material for active magnetic refrigeration at low temperatures.
Mn3Sn2 被认为是磁制冷的理想材料。它连续经历了两次铁磁转变（TC1 = 262 K 和 TC2 = 227 K）和一次反铁磁转变（TN = 192 K）。在此，我们首次报告了利用 Bi 通量制备 Mn3Sn2 单晶的过程。我们沿晶体的三个主要晶体学方向研究了由此产生的各向异性磁特性和磁致效应。在低磁场下发现了磁感应强度的显著各向异性和多个磁场诱导的元磁转变，而磁钙效应几乎是各向同性的，且大于多晶的磁钙效应。沿 c 轴的磁场变化为 μ0ΔH = 5 T 时，在 TC1 附近的最大磁熵变化为 -ΔSM = 4.01 J-kg-1-K-1，相应的制冷剂容量为 1750 mJ-cm-3。结合更宽的冷却温度跨度（∼ 80 K），我们的结果表明 Mn3Sn2 单晶是一种极具吸引力的低温主动磁制冷候选工作材料。
{"title":"Highly Anisotropic Magnetism and Nearly Isotropic Magnetocaloric Effect in Mn3Sn2 Single Crystals","authors":"Jianli Bai, Qingxin Dong, Libo Zhang, Qiaoyu Liu, Jingwen Cheng, Pinyu Liu, Cundong Li, Yingrui Sun, Yu Huang, Zhian Ren, Genfu Chen","doi":"10.1088/0256-307x/40/12/127501","DOIUrl":"https://doi.org/10.1088/0256-307x/40/12/127501","url":null,"abstract":"Mn<sub>3</sub>Sn<sub>2</sub> has been proposed as an ideal material for magnetic refrigeration. It undergoes two successive ferromagnetic transitions (<italic toggle=\"yes\">T</italic>\u0000<sub>C1</sub> = 262 K and <italic toggle=\"yes\">T</italic>\u0000<sub>C2</sub> = 227 K) and one antiferromagnetic transition (<italic toggle=\"yes\">T</italic>\u0000<sub>N</sub> = 192 K). Herein we report, for the first time, the preparation of single crystals of Mn<sub>3</sub>Sn<sub>2</sub> from Bi flux. The resultant anisotropic magnetic properties and magnetocaloric effect are investigated along the three principal crystallographic directions of the crystal. Significant anisotropy of magnetic susceptibility and multiple field-induced metamagnetic transitions were found at low fields, whereas the magnetocaloric effect was found to be almost isotropic and larger than that of the polycrystalline one. The maximum magnetic entropy change amounts to −Δ<italic toggle=\"yes\">S</italic>\u0000<sub>M</sub> = 4.01 J⋅kg<sup>−1</sup>⋅K<sup>−1</sup> near <italic toggle=\"yes\">T</italic>\u0000<sub>C1</sub> under a magnetic field change of <italic toggle=\"yes\">μ</italic>\u0000<sub>0</sub>Δ<italic toggle=\"yes\">H</italic> = 5 T along the <italic toggle=\"yes\">c</italic>-axis, with the corresponding refrigerant capacity of 1750 mJ⋅cm<sup>−3</sup>. Combined with a much wider cooling temperature span (∼ 80 K), our results demonstrate Mn<sub>3</sub>Sn<sub>2</sub> single crystal to be an attractive candidate working material for active magnetic refrigeration at low temperatures.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":"78 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139057874","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}
Pub Date : 2023-11-29DOI: 10.1088/0256-307x/41/1/017101
J. M. Wang, H. J. Qian, Q. Jiang, S. Qiao, M. Ye
Magnetic topological semimetals have been at the forefront of condensed matter physics due to their ability to exhibit exotic transport phenomena. Investigating the interplay between magnetic and topological orders in systems with broken time-reversal symmetry is crucial for realizing non-trivial quantum effects. In this work, we delved into the electronic structure of the rare-earth based antiferromagnetic Dirac semimetal EuMg2Bi2 using first-principles calculations and angleresolved photoemission spectroscopy. Our calculations revealed that the spin-orbit coupling (SOC) in EuMg2Bi2 prompts an insulator to topological semimetal transition, with the Dirac bands protected by crystal symmetries. Linear dispersive states near the Fermi level, primarily originating from Bi 6p orbitals, were observed on both the (001) and (100) surfaces, confirming that EuMg2Bi2 is a three-dimensional (3D) topological Dirac semimetal. This research offers pivotal insights into the interplay between magnetism, SOC and topological phase transitions in spintronics applications.
{"title":"Magnetic topological Dirac semimetal transition driven by SOC in EuMg2Bi2","authors":"J. M. Wang, H. J. Qian, Q. Jiang, S. Qiao, M. Ye","doi":"10.1088/0256-307x/41/1/017101","DOIUrl":"https://doi.org/10.1088/0256-307x/41/1/017101","url":null,"abstract":"Magnetic topological semimetals have been at the forefront of condensed matter physics due to their ability to exhibit exotic transport phenomena. Investigating the interplay between magnetic and topological orders in systems with broken time-reversal symmetry is crucial for realizing non-trivial quantum effects. In this work, we delved into the electronic structure of the rare-earth based antiferromagnetic Dirac semimetal EuMg2Bi2 using first-principles calculations and angleresolved photoemission spectroscopy. Our calculations revealed that the spin-orbit coupling (SOC) in EuMg2Bi2 prompts an insulator to topological semimetal transition, with the Dirac bands protected by crystal symmetries. Linear dispersive states near the Fermi level, primarily originating from Bi 6p orbitals, were observed on both the (001) and (100) surfaces, confirming that EuMg2Bi2 is a three-dimensional (3D) topological Dirac semimetal. This research offers pivotal insights into the interplay between magnetism, SOC and topological phase transitions in spintronics applications.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":"2 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139212244","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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