The equilibrium states of multisublattice magnets with spin s = 3/2 are studied. The developed approach essentially uses the symmetry properties of the Hamiltonian, the idea of the residual symmetry of the equilibrium state, and the form of order parameters. On this basis, without using any model assumptions, classification equations for order parameters are obtained. Solutions of these equations are given in cases of broken SU(3) and SU(4) symmetries. The equilibrium structure of order parameters is presented in terms of the spontaneous anisotropy parameters of the residual symmetry generator.
研究了自旋 s = 3/2 的多子晶格磁体的平衡态。所开发的方法主要利用了哈密顿的对称性、平衡态的残余对称性思想以及阶次参数的形式。在此基础上，无需使用任何模型假设，即可获得阶次参数的分类方程。在 SU(3) 和 SU(4) 对称性被破坏的情况下，给出了这些方程的解。用残余对称性发生器的自发各向异性参数给出了阶次参数的平衡结构。
{"title":"On the classification of degenerate equilibrium states of multisublattice SU(4) magnets with spin s = 3/2","authors":"M. Yu. Kovalevsky","doi":"10.1063/10.0024325","DOIUrl":"https://doi.org/10.1063/10.0024325","url":null,"abstract":"The equilibrium states of multisublattice magnets with spin s = 3/2 are studied. The developed approach essentially uses the symmetry properties of the Hamiltonian, the idea of the residual symmetry of the equilibrium state, and the form of order parameters. On this basis, without using any model assumptions, classification equations for order parameters are obtained. Solutions of these equations are given in cases of broken SU(3) and SU(4) symmetries. The equilibrium structure of order parameters is presented in terms of the spontaneous anisotropy parameters of the residual symmetry generator.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"13 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139945924","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}
D. V. Laptiev, O. O. Kryvchikov, Yu. V. Savin, V. V. Slavin
Using the Kramers–Wannier transfer matrix method, we studied several decorated Ising chains. The exact expressions for thermodynamic characteristics, including the ground state characteristics, were obtained. We considered several modeling chains with different signs and absolute values of exchange constants for the nearest- and the next-nearest neighbors. For these models, we calculated the magnetization curves. The critical values of magnetic fields and corresponding magnetization plateau parameters were obtained. Analytic expressions for the ground state entropy were obtained for the chains with different interaction constants. The dependencies of the number of states with minimum energy (the degeneration of the ground state) as the function of the number of particles were found. It was shown that these dependencies are expressed in terms of well-known numerical sequences, namely Lucas numbers and Pell numbers, which, in the limit of a large number of particles, are proportional to the powers of the golden and silver sections. Therefore, the ground state entropy (per particle) of the systems under consideration can be described in terms of these sections and, therefore, is nonzero.
{"title":"Magnetic properties of the frustrated Ising chain","authors":"D. V. Laptiev, O. O. Kryvchikov, Yu. V. Savin, V. V. Slavin","doi":"10.1063/10.0024328","DOIUrl":"https://doi.org/10.1063/10.0024328","url":null,"abstract":"Using the Kramers–Wannier transfer matrix method, we studied several decorated Ising chains. The exact expressions for thermodynamic characteristics, including the ground state characteristics, were obtained. We considered several modeling chains with different signs and absolute values of exchange constants for the nearest- and the next-nearest neighbors. For these models, we calculated the magnetization curves. The critical values of magnetic fields and corresponding magnetization plateau parameters were obtained. Analytic expressions for the ground state entropy were obtained for the chains with different interaction constants. The dependencies of the number of states with minimum energy (the degeneration of the ground state) as the function of the number of particles were found. It was shown that these dependencies are expressed in terms of well-known numerical sequences, namely Lucas numbers and Pell numbers, which, in the limit of a large number of particles, are proportional to the powers of the golden and silver sections. Therefore, the ground state entropy (per particle) of the systems under consideration can be described in terms of these sections and, therefore, is nonzero.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"8 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139945927","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}
D. E. Hurova, S. V. Cherednichenko, N. A. Aksenova, N. А. Vinnikov, А. V. Dolbin, N. N. Galtsov
In this work, using X-ray diffractometry and optical microscopy, studies of epoxy-based composites containing a small amount of nanostructures (nanotubes and graphene oxide) were carried out. The test substance was used to glue two aluminum plates together, and then they were stretched in different directions until rupture. Using X-ray diffractometry, it was found that the introduction of an impurity does not lead to the formation of crystalline inclusions in the adhesive layer. For samples with an admixture of graphene oxide, the formation of graphene oxide conglomerates with a linear size of the order of 10 μm is observed.
在这项工作中，利用 X 射线衍射仪和光学显微镜对含有少量纳米结构（纳米管和氧化石墨烯）的环氧基复合材料进行了研究。试验物质用于将两块铝板粘合在一起，然后将它们向不同方向拉伸直至断裂。利用 X 射线衍射仪发现，引入杂质不会导致在粘合剂层中形成晶体夹杂物。对于掺入了氧化石墨烯的样品，可以观察到线性尺寸为 10 μm 的氧化石墨烯团块的形成。
{"title":"Structural studies of epoxy resin with impurities of carbon nanostructures","authors":"D. E. Hurova, S. V. Cherednichenko, N. A. Aksenova, N. А. Vinnikov, А. V. Dolbin, N. N. Galtsov","doi":"10.1063/10.0024329","DOIUrl":"https://doi.org/10.1063/10.0024329","url":null,"abstract":"In this work, using X-ray diffractometry and optical microscopy, studies of epoxy-based composites containing a small amount of nanostructures (nanotubes and graphene oxide) were carried out. The test substance was used to glue two aluminum plates together, and then they were stretched in different directions until rupture. Using X-ray diffractometry, it was found that the introduction of an impurity does not lead to the formation of crystalline inclusions in the adhesive layer. For samples with an admixture of graphene oxide, the formation of graphene oxide conglomerates with a linear size of the order of 10 μm is observed.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"8 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139945976","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}
Using Tokuda’s improved linear combination operator method and variational technique, the expression of the polaron effective mass in an parabolic quantum well is derived. Due to the spin-orbit interaction, the effective mass of polaron splits into two branches. The dependence of effective mass on temperature and mean number phonons is discussed by numerical calculation. The effective mass of polaron is an increasing function of temperature and mean number phonons. The absolute value of total spin splitting effective mass increases with the increase in temperature and spin-orbit coupling parameter, and decreases with the increase in velocity. Due to the heavy hole characteristic, the spin splitting effective mass is negative.
{"title":"Temperature effect and Rashba effect of polaron in a parabolic quantum well","authors":"Shu-Ping Shan","doi":"10.1063/10.0024330","DOIUrl":"https://doi.org/10.1063/10.0024330","url":null,"abstract":"Using Tokuda’s improved linear combination operator method and variational technique, the expression of the polaron effective mass in an parabolic quantum well is derived. Due to the spin-orbit interaction, the effective mass of polaron splits into two branches. The dependence of effective mass on temperature and mean number phonons is discussed by numerical calculation. The effective mass of polaron is an increasing function of temperature and mean number phonons. The absolute value of total spin splitting effective mass increases with the increase in temperature and spin-orbit coupling parameter, and decreases with the increase in velocity. Due to the heavy hole characteristic, the spin splitting effective mass is negative.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"2013 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139946197","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 rotation of a magnetic vortex in a ferromagnet with a local smooth change in the exchange interaction is considered. The frequency of this precession is found for all distances of the vortex from defect center. The rotation velocity of the vortex nonmonotonically depends on the distance to the center, reaching a maximum at a distance of the order of the characteristic dimension of the defect. The decrease in velocity at large distances agrees with the data known in the literature. Accounting of attenuation leads to the vortex escape the defect or falling onto it along a logarithmic spiral.
{"title":"Dynamics of magnetic vortices in the field of local inhomogeneity of a ferromagnet","authors":"A. S. Kovalev","doi":"10.1063/10.0024322","DOIUrl":"https://doi.org/10.1063/10.0024322","url":null,"abstract":"The rotation of a magnetic vortex in a ferromagnet with a local smooth change in the exchange interaction is considered. The frequency of this precession is found for all distances of the vortex from defect center. The rotation velocity of the vortex nonmonotonically depends on the distance to the center, reaching a maximum at a distance of the order of the characteristic dimension of the defect. The decrease in velocity at large distances agrees with the data known in the literature. Accounting of attenuation leads to the vortex escape the defect or falling onto it along a logarithmic spiral.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"141 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139946314","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}
V. O. Cheranovskii, E. V. Ezerskaya, S. Ye. Kononenko
The peculiarities of the energy spectrum of the decorated mixed spin two-leg ladder system having three spin unit cells have been studied by the perturbation theory in the limit of dominant spin coupling in ladder rungs. It is shown, that despite the singlet ground state, this spin ladder may have an intermediate plateau in a low-temperature magnetization profile. The existence of a similar plateau was shown also in the case of some intermediate values of coupling parameters by means of exact diagonalization study of small ladder clusters and by the density-matrix renormalization group calculations. We also found that the Ising type of interactions in ladder rungs may lead to the disappearance of the above intermediate magnetization plateau for the corresponding isotropic spin ladder.
{"title":"The energy spectrum and magnetization profile of the decorated spin ladder systems","authors":"V. O. Cheranovskii, E. V. Ezerskaya, S. Ye. Kononenko","doi":"10.1063/10.0024327","DOIUrl":"https://doi.org/10.1063/10.0024327","url":null,"abstract":"The peculiarities of the energy spectrum of the decorated mixed spin two-leg ladder system having three spin unit cells have been studied by the perturbation theory in the limit of dominant spin coupling in ladder rungs. It is shown, that despite the singlet ground state, this spin ladder may have an intermediate plateau in a low-temperature magnetization profile. The existence of a similar plateau was shown also in the case of some intermediate values of coupling parameters by means of exact diagonalization study of small ladder clusters and by the density-matrix renormalization group calculations. We also found that the Ising type of interactions in ladder rungs may lead to the disappearance of the above intermediate magnetization plateau for the corresponding isotropic spin ladder.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"33 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139946179","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 dynamical characteristics of one-dimensional molecular aggregate with the randomness in exciton hopping is considered. We show that the randomness of the distribution of signs of the exciton hopping of the aggregate dramatically changes the dynamical characteristics. In the homogeneous case, the dynamical characteristics of the molecular aggregate manifest narrow lines at edges of the band of Frenkel excitons of the aggregate. On the other hand, we show that the considered randomness yields nonzero contributions to the dynamical characteristics of all excitons of the band.
{"title":"Dynamical characteristics of inhomogeneous molecular aggregates","authors":"I. Yu. Ropakova, A. A. Zvyagin","doi":"10.1063/10.0024331","DOIUrl":"https://doi.org/10.1063/10.0024331","url":null,"abstract":"The dynamical characteristics of one-dimensional molecular aggregate with the randomness in exciton hopping is considered. We show that the randomness of the distribution of signs of the exciton hopping of the aggregate dramatically changes the dynamical characteristics. In the homogeneous case, the dynamical characteristics of the molecular aggregate manifest narrow lines at edges of the band of Frenkel excitons of the aggregate. On the other hand, we show that the considered randomness yields nonzero contributions to the dynamical characteristics of all excitons of the band.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"17 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139945923","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}
V. I. Sokolenko, A. O. Chupikov, M. M. Pylypenko, M. B. Lazareva, O. Yu. Roskoshna
The effect of hydrogenation from the gas phase on the change in the character of the temperature dependence of the electrical resistivity ρ(T) in the range of 77–300 K and the temperatures of phase magnetic transformations (Curie temperature TC and Néel temperature TN) of dysprosium was studied. It follows from the experimental data and their analysis that, within the framework of the indirect exchange ideas, the decreases in TC, TN and the contribution to ρ(T) related to electron scattering in the paramagnetic phase are interrelated. It has been suggested that hydrogenation effects may be related to changes in microscopic parameters: a decrease in the density of states at the Fermi level, an increase in the Fermi energy, and a decrease in the effective mass of carriers and the s-f exchange parameter.
{"title":"The effect of hydrogenation on the electrophysics and magnetic characteristics of dysprosium","authors":"V. I. Sokolenko, A. O. Chupikov, M. M. Pylypenko, M. B. Lazareva, O. Yu. Roskoshna","doi":"10.1063/10.0024323","DOIUrl":"https://doi.org/10.1063/10.0024323","url":null,"abstract":"The effect of hydrogenation from the gas phase on the change in the character of the temperature dependence of the electrical resistivity ρ(T) in the range of 77–300 K and the temperatures of phase magnetic transformations (Curie temperature TC and Néel temperature TN) of dysprosium was studied. It follows from the experimental data and their analysis that, within the framework of the indirect exchange ideas, the decreases in TC, TN and the contribution to ρ(T) related to electron scattering in the paramagnetic phase are interrelated. It has been suggested that hydrogenation effects may be related to changes in microscopic parameters: a decrease in the density of states at the Fermi level, an increase in the Fermi energy, and a decrease in the effective mass of carriers and the s-f exchange parameter.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"2013 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139945975","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 theory for the low-temperature behavior of sound velocities (and related elastic modules) in the external magnetic field in UTe2 is proposed. The theory is based on the dual model. The model takes into account 5f2 electrons of U ions: both itinerant electrons (part of which form pairs, responsible for the superconductivity) and localized ones. The theory explains the metamagnetic-like jumps in the magnetic field observed at low temperature in UTe2.
提出了碲化镉 2 外磁场中声速（及相关弹性模块）的低温行为理论。该理论基于双重模型。该模型考虑了 U 离子的 5f2 电子：巡回电子（其中部分电子形成对，负责超导性）和局部电子。该理论解释了在 UTe2 中低温下观察到的类似元磁性的磁场跃迁。
{"title":"Low-temperature magnetic field behavior of elastic modules in UTe2","authors":"A. A. Zvyagin, G. A. Zvyagina","doi":"10.1063/10.0024324","DOIUrl":"https://doi.org/10.1063/10.0024324","url":null,"abstract":"The theory for the low-temperature behavior of sound velocities (and related elastic modules) in the external magnetic field in UTe2 is proposed. The theory is based on the dual model. The model takes into account 5f2 electrons of U ions: both itinerant electrons (part of which form pairs, responsible for the superconductivity) and localized ones. The theory explains the metamagnetic-like jumps in the magnetic field observed at low temperature in UTe2.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"178 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139945921","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}
V. V. Sumarokov, A. V. Dolbin, A. Jeżowski, D. Szewczyk, D. Gnida, N. A. Vinnikov, M. I. Bagatskii
The specific heat of thermally reduced graphene oxide (trGO) was measured by a thermal relaxation method in the temperature range from 0.3 to 275 K. It was found that the temperature dependence of the heat capacity С(Т)/T vs T2 of trGO is nonmonotonic. It has been established that in the temperature range of 0.3–6 K there is an anomalous behavior of the temperature dependence of the heat capacity trGO, sharply changing its character. It is assumed that this anomaly is due to the influence of impurities and defects, structural features.
热松弛法测量了热还原氧化石墨烯（trGO）在 0.3 至 275 K 温度范围内的比热。研究发现，在 0.3-6 K 的温度范围内，trGO 的热容量与温度的关系存在异常行为，其特征发生了急剧变化。据推测，这种反常现象是由于杂质和缺陷、结构特征的影响造成的。
{"title":"Short notes: Measurements on the heat capacity of thermal reduced graphene oxide down to 0.3 K","authors":"V. V. Sumarokov, A. V. Dolbin, A. Jeżowski, D. Szewczyk, D. Gnida, N. A. Vinnikov, M. I. Bagatskii","doi":"10.1063/10.0024332","DOIUrl":"https://doi.org/10.1063/10.0024332","url":null,"abstract":"The specific heat of thermally reduced graphene oxide (trGO) was measured by a thermal relaxation method in the temperature range from 0.3 to 275 K. It was found that the temperature dependence of the heat capacity С(Т)/T vs T2 of trGO is nonmonotonic. It has been established that in the temperature range of 0.3–6 K there is an anomalous behavior of the temperature dependence of the heat capacity trGO, sharply changing its character. It is assumed that this anomaly is due to the influence of impurities and defects, structural features.","PeriodicalId":18077,"journal":{"name":"Low Temperature Physics","volume":"16 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139946176","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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