Pub Date : 2024-11-04DOI: 10.1103/physrevb.110.174405
Rai M. Menezes, Milorad V. Milošević
While the transition between skyrmionic and nontopological states has been widely explored as a bit operation for information transport and storage in spintronic devices, the ultrafast dynamics of such transitions remains challenging to observe and understand. Here, we utilize spin-dynamics simulations and harmonic transition state theory (HTST) to provide an in-depth analysis of the nucleation of skyrmionic states in helimagnets. We reveal a persistent blinking (creation-annihilation) phenomenon of these topological states under specific conditions near the phase boundary between skyrmion and conical states. Through a minimum-energy path analysis, we elucidate that this blinking behavior is favored by the formation of chiral bobber (CB) surface states and that the collapse of CBs differs from that of skyrmions in thin films due to their different oscillation modes. We further employ HTST to estimate the typical blinking time as a function of the applied magnetic field and temperature. Finally, we illustrate the practical use of skyrmion blinking for controlled probabilistic computing, exemplified by a skyrmion-based random-number generator.
{"title":"Skyrmion blinking from the conical phase","authors":"Rai M. Menezes, Milorad V. Milošević","doi":"10.1103/physrevb.110.174405","DOIUrl":"https://doi.org/10.1103/physrevb.110.174405","url":null,"abstract":"While the transition between skyrmionic and nontopological states has been widely explored as a bit operation for information transport and storage in spintronic devices, the ultrafast dynamics of such transitions remains challenging to observe and understand. Here, we utilize spin-dynamics simulations and harmonic transition state theory (HTST) to provide an in-depth analysis of the nucleation of skyrmionic states in helimagnets. We reveal a persistent blinking (creation-annihilation) phenomenon of these topological states under specific conditions near the phase boundary between skyrmion and conical states. Through a minimum-energy path analysis, we elucidate that this blinking behavior is favored by the formation of chiral bobber (CB) surface states and that the collapse of CBs differs from that of skyrmions in thin films due to their different oscillation modes. We further employ HTST to estimate the typical blinking time as a function of the applied magnetic field and temperature. Finally, we illustrate the practical use of skyrmion blinking for controlled probabilistic computing, exemplified by a skyrmion-based random-number generator.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"34 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574681","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 : 2024-11-04DOI: 10.1103/physrevb.110.205405
O. M. Bahrova, S. V. Koniakhin
This paper is devoted to a comprehensive theoretical study of asymmetric (skew) scattering in photonic graphene, with the main focus on its realization with semiconductor microcavity exciton-polaritons. As an important consequence of the skew scattering, we prove the appearance of the ratchet effect in this system. Triangular defects in the form of missing micropillars in a regular honeycomb lattice are considered to be ones that break the spatial inversion symmetry, thus providing the possibility of the ratchet effect. By means of the numerical solution of the effective Schrödinger equation, we provide microscopical insight into the process of skew scattering and determine indicatrices, cross sections, and asymmetry parameters. In a system with multiple coherently oriented triangular defects, a macroscopic ratchet effect occurs as a unidirectional flux upon noiselike initial conditions. Our study broadens the concept of ratchet phenomena in the field of photonics and optics of exciton-polaritons.
{"title":"Skew scattering and ratchet effect in photonic graphene","authors":"O. M. Bahrova, S. V. Koniakhin","doi":"10.1103/physrevb.110.205405","DOIUrl":"https://doi.org/10.1103/physrevb.110.205405","url":null,"abstract":"This paper is devoted to a comprehensive theoretical study of asymmetric (skew) scattering in photonic graphene, with the main focus on its realization with semiconductor microcavity exciton-polaritons. As an important consequence of the skew scattering, we prove the appearance of the ratchet effect in this system. Triangular defects in the form of missing micropillars in a regular honeycomb lattice are considered to be ones that break the spatial inversion symmetry, thus providing the possibility of the ratchet effect. By means of the numerical solution of the effective Schrödinger equation, we provide microscopical insight into the process of skew scattering and determine indicatrices, cross sections, and asymmetry parameters. In a system with multiple coherently oriented triangular defects, a macroscopic ratchet effect occurs as a unidirectional flux upon noiselike initial conditions. Our study broadens the concept of ratchet phenomena in the field of photonics and optics of exciton-polaritons.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"61 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579988","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 : 2024-11-04DOI: 10.1103/physrevb.110.199901
D. L. Kunwar, S. R. Panday, Y. Deng, S. Ran, R. E. Baumbach, M. B. Maple, Carmen C. Almasan, M. Dzero
DOI:https://doi.org/10.1103/PhysRevB.110.199901
DOI:https://doi.org/10.1103/PhysRevB.110.199901
{"title":"Erratum: Heat capacity ofURu2−𝑥Os𝑥Si2at low temperatures [Phys. Rev. B105, L041106 (2022)]","authors":"D. L. Kunwar, S. R. Panday, Y. Deng, S. Ran, R. E. Baumbach, M. B. Maple, Carmen C. Almasan, M. Dzero","doi":"10.1103/physrevb.110.199901","DOIUrl":"https://doi.org/10.1103/physrevb.110.199901","url":null,"abstract":"<span>DOI:</span><span>https://doi.org/10.1103/PhysRevB.110.199901</span>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"75 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142574688","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 : 2024-11-04DOI: 10.1103/physrevb.110.205106
David Mikhail, Stephan Rachel
The interplay and competition of topology and electron–electron interactions have fascinated researchers since the discovery of topological insulators. The Su–Schrieffer–Heeger–Hubbard (SSH-Hubbard) model is a prototypical model which includes both nontrivial topology and interactions. Due to its simplicity, there are several artificial quantum systems which can realize such a model to a good approximation. Here we focus on the quarter-filled case, where interactions and dimerization open a charge gap. In particular, we study the single-particle spectral function for the extended SSH-Hubbard model with magnetic field and explore several parameter limits where effective model descriptions arise. In the strongly dimerized limit, we show that the low-energy excitations of the spectral function resemble a half-filled Hubbard model with effective dimer sites and renormalized couplings. For strong magnetic field and interactions, we find physics akin to the spinless Su–Schrieffer–Heeger model at half filling, featuring a noninteracting topological phase transition. Moreover, in light of the recent realization of this model in quantum dot simulation, we provide evidence for the stability of the topological phase towards moderate nonlocal interactions in the experimentally expected parameter range.
{"title":"Su-Schrieffer-Heeger-Hubbard model at quarter filling: Effects of magnetic field and nonlocal interactions","authors":"David Mikhail, Stephan Rachel","doi":"10.1103/physrevb.110.205106","DOIUrl":"https://doi.org/10.1103/physrevb.110.205106","url":null,"abstract":"The interplay and competition of topology and electron–electron interactions have fascinated researchers since the discovery of topological insulators. The Su–Schrieffer–Heeger–Hubbard (SSH-Hubbard) model is a prototypical model which includes both nontrivial topology and interactions. Due to its simplicity, there are several artificial quantum systems which can realize such a model to a good approximation. Here we focus on the quarter-filled case, where interactions and dimerization open a charge gap. In particular, we study the single-particle spectral function for the extended SSH-Hubbard model with magnetic field and explore several parameter limits where effective model descriptions arise. In the strongly dimerized limit, we show that the low-energy excitations of the spectral function resemble a half-filled Hubbard model with effective dimer sites and renormalized couplings. For strong magnetic field and interactions, we find physics akin to the spinless Su–Schrieffer–Heeger model at half filling, featuring a noninteracting topological phase transition. Moreover, in light of the recent realization of this model in quantum dot simulation, we provide evidence for the stability of the topological phase towards moderate nonlocal interactions in the experimentally expected parameter range.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"7 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579878","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 : 2024-11-04DOI: 10.1103/physrevb.110.195103
Yueqing Chang, Sonali Joshi, Lucas K. Wagner
We present a generalized framework, renormalized density matrix downfolding (RDMD), to derive systematically improvable, highly accurate, and nonperturbative effective models from ab initio calculations. This framework moves beyond the common role of ab initio calculations as calculating the parameters of a proposed Hamiltonian. Instead, RDMD provides the capability to decide whether a given effective Hilbert space can be identified from the ab initio data and assess the relative quality of ansatz Hamiltonians. Any method of ab initio solution can be used as a data source, and as the ab initio solutions improve, the resultant model also improves. We demonstrate the framework in an application to the downfolding of a hydrogen chain to a spin model, in which we find the interatomic separations for which a nonperturbative mapping can be made even in the strong coupling regime where standard methods fail, and compute a renormalized spin model Hamiltonian that quantitatively reproduces the ab initio dynamics.
我们提出了一个广义框架--重归一化密度矩阵折叠（RDMD），以从原子序数计算中推导出系统改进的、高度精确的非微扰有效模型。这一框架超越了演算法在计算拟议哈密顿参数中的常见作用。取而代之的是，RDMD 能够决定是否能从原子序数数据中识别出给定的有效希尔伯特空间，并评估拟哈密顿的相对质量。任何从头开始求解的方法都可以用作数据源，随着从头开始求解的改进，结果模型也会随之改进。我们在氢链向自旋模型下折的应用中演示了这一框架，在这一应用中，我们找到了即使在标准方法失效的强耦合机制中也能做出非微扰映射的原子间分离，并计算出了定量再现了 ab initio 动力学的重规范化自旋模型哈密顿。
{"title":"Renormalized density matrix downfolding: A rigorous framework in learning emergent models fromab initiomany-body calculations","authors":"Yueqing Chang, Sonali Joshi, Lucas K. Wagner","doi":"10.1103/physrevb.110.195103","DOIUrl":"https://doi.org/10.1103/physrevb.110.195103","url":null,"abstract":"We present a generalized framework, renormalized density matrix downfolding (RDMD), to derive systematically improvable, highly accurate, and nonperturbative effective models from <i>ab initio</i> calculations. This framework moves beyond the common role of <i>ab initio</i> calculations as calculating the parameters of a proposed Hamiltonian. Instead, RDMD provides the capability to decide whether a given effective Hilbert space can be identified from the <i>ab initio</i> data and assess the relative quality of <i>ansatz</i> Hamiltonians. Any method of <i>ab initio</i> solution can be used as a data source, and as the <i>ab initio</i> solutions improve, the resultant model also improves. We demonstrate the framework in an application to the downfolding of a hydrogen chain to a spin model, in which we find the interatomic separations for which a nonperturbative mapping can be made even in the strong coupling regime where standard methods fail, and compute a renormalized spin model Hamiltonian that quantitatively reproduces the <i>ab initio</i> dynamics.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"242 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579952","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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