arXiv - PHYS - Superconductivity最新文献_第8页

Spectroscopic evidence for a first-order transition to the orbital Fulde-Ferrell-Larkin-Ovchinnikov state 向轨道 Fulde-Ferrell-Larkin-Ovchinnikov 状态一阶转变的光谱证据

arXiv - PHYS - Superconductivity Pub Date : 2024-08-31 DOI: arxiv-2409.00373

Zongzheng Cao, Menghan Liao, Hongyi Yan, Yuying Zhu, Liguo Zhang, Kenji Watanabe, Takashi Taniguchi, Alberto F. Morpurgo, Haiwen Liu, Qi-Kun Xue, Ding Zhang

{"title":"Spectroscopic evidence for a first-order transition to the orbital Fulde-Ferrell-Larkin-Ovchinnikov state","authors":"Zongzheng Cao, Menghan Liao, Hongyi Yan, Yuying Zhu, Liguo Zhang, Kenji Watanabe, Takashi Taniguchi, Alberto F. Morpurgo, Haiwen Liu, Qi-Kun Xue, Ding Zhang","doi":"arxiv-2409.00373","DOIUrl":"https://doi.org/arxiv-2409.00373","url":null,"abstract":"A conventional superconducting state may be replaced by another\u0000dissipationless state hosting Cooper pairs with a finite momentum, leaving\u0000thermodynamic footprints for such a phase transition. Recently, a novel type of\u0000finite momentum pairing, so-called orbital Fulde-Ferrell-Larkin-Ovchinnikov\u0000(FFLO) state, has been proposed to occur in spin-orbit coupled superconductors\u0000such as bilayer $2mathrm{H-NbSe_{2}}$. So far, a thermodynamic demonstration,\u0000which is key for establishing this exotic phase, has been lacking. Here, we\u0000reveal a first-order quantum phase transition to the orbital FFLO state in\u0000tunneling spectroscopic measurements on multilayer $2mathrm{H-NbSe_{2}}$. The\u0000phase transition manifests itself as a sudden enhancement of the\u0000superconducting gap at an in-plane magnetic field $B_{//}$ well below the upper\u0000critical field. Furthermore, this transition shows prominent hysteresis by\u0000sweeping $B_{//}$ back and forth and quickly disappears once the magnetic field\u0000is tilted away from the sample plane by less than one degree. We obtain a\u0000comprehensive phase diagram for the orbital FFLO state and compare it with the\u0000theoretical calculation that takes into account the rearrangement of Josephson\u0000vortices. Our work elucidates the microscopic mechanism for the emergence of\u0000the orbital FFLO state.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Increasing superconducting $T_c$ by layering in the attractive Hubbard model 在有吸引力的哈伯德模型中通过分层增加超导 $T_c$

arXiv - PHYS - Superconductivity Pub Date : 2024-08-30 DOI: arxiv-2408.17405

Rodrigo A. Fontenele, Natanael C. Costa, Thereza Paiva, Raimundo R. dos Santos

{"title":"Increasing superconducting $T_c$ by layering in the attractive Hubbard model","authors":"Rodrigo A. Fontenele, Natanael C. Costa, Thereza Paiva, Raimundo R. dos Santos","doi":"arxiv-2408.17405","DOIUrl":"https://doi.org/arxiv-2408.17405","url":null,"abstract":"The attractive Hubbard model has become a model readily realizable with\u0000ultracold atoms on optical lattices. However, the superconducting (superfluid)\u0000critical temperatures, $T_c$'s, are still somewhat smaller than the lowest\u0000temperatures achieved in experiments. Here we consider two possible routes,\u0000generically called layering, to increase $T_c$: a bilayer and a simple cubic\u0000lattice, both with tunable hopping, $t_z$, between attractive Hubbard planes.\u0000We have performed minus-sign--free determinant quantum Monte Carlo simulations\u0000to calculate response functions such as pairing correlation functions, uniform\u0000spin susceptibility, and double occupancy, through which we map out some\u0000physical properties. We have found that by a judicious choice of fillings and\u0000intensity of on-site attraction, a bilayer can exhibit $T_c$'s between 1.5 and\u00001.7 times those of the single layer; for the simple-cubic lattice the\u0000enhancement can be 30% larger than the maximum for the single layer. We also\u0000check the accuracy of both a BCS-like estimate for $T_c$ in the attractive\u0000Hubbard model, as well as of an upper bound for $T_c$ based on the superfluid\u0000density.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Large-$N$ Approach to Magnetic Impurities in Superconductors 超导体中磁杂质的大 N$ 方法

arXiv - PHYS - Superconductivity Pub Date : 2024-08-30 DOI: arxiv-2408.17281

Chen-How Huang, Alejandro M. Lobos, Miguel A. Cazalilla

{"title":"A Large-$N$ Approach to Magnetic Impurities in Superconductors","authors":"Chen-How Huang, Alejandro M. Lobos, Miguel A. Cazalilla","doi":"arxiv-2408.17281","DOIUrl":"https://doi.org/arxiv-2408.17281","url":null,"abstract":"Quantum spin impurities coupled to superconductors are under intense\u0000investigation for their relevance to fundamental research as well as the\u0000prospects to engineer novel quantum phases of matter. Here we develop a\u0000large-$N$ mean-field theory of a strongly coupled spin-$tfrac{1}{2}$ quantum\u0000impurity in a conventional $s$-wave superconductor. The approach is benchmarked\u0000against Wilson's numerical renormalization group (NRG). While the large-$N$\u0000method is not applicable in the weak-coupling regime where the Kondo\u0000temperature $T_K$ is smaller than the superconducting gap $Delta$, it performs\u0000very well in the strong coupling regime where $T_K gtrsim Delta$, thus\u0000allowing to obtain a reasonably accurate description of experimentally relevant\u0000quantities. The latter includes the energy of the Yu-Shiba-Rusinov subgap\u0000states, their spectral weight, as well as the local density of continuum\u0000states. The method provides a reliable analytical tool that complements other\u0000perturbative and non-perturbative methods, and can be extended to more complex\u0000impurity models for which NRG may be not easily applicable.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimization of Superconducting Niobium Nitride Thin Films via High-Power Impulse Magnetron Sputtering 通过大功率脉冲磁控溅射优化超导氮化铌薄膜

arXiv - PHYS - Superconductivity Pub Date : 2024-08-30 DOI: arxiv-2408.17256

Hudson T. Horne, Collin M. Hugo, Brandon C. Reid, Daniel F. Santavicca

引用次数: 0

Non-Hermitian multiterminal phase-biased Josephson junctions 非ermitian 多端相位偏置约瑟夫森结

arXiv - PHYS - Superconductivity Pub Date : 2024-08-30 DOI: arxiv-2408.17260

Jorge Cayao, Masatoshi Sato

引用次数: 0

Nonreciprocal Josephson current through a conical magnet 通过锥形磁体的非互易约瑟夫森电流

arXiv - PHYS - Superconductivity Pub Date : 2024-08-30 DOI: arxiv-2409.00223

Lina Johnsen Kamra, Liang Fu

引用次数: 0

Structural Evolution from Hyper-Honeycomb to Honeycomb Networks and Superconductivity in LaPt$_x$Si$_{2-x}$ LaPt$_x$Si$_{2-x}$ 中从超蜂窝到蜂窝网络的结构演变和超导性

arXiv - PHYS - Superconductivity Pub Date : 2024-08-30 DOI: arxiv-2408.17033

Sitaram Ramakrishnan, Tatsuya Yamakawa, Ryohei Oishi, Soichiro Yamane, Atsutoshi Ikeda, Masaki Kado, Yasuyuki Shimura, Toshiro Takabatake, Takahiro Onimaru, Yasuhiro Shibata, Arumugam Thamizhavel, Srinivasan Ramakrishnan, Shingo Yonezawa, Minoru Nohara

{"title":"Structural Evolution from Hyper-Honeycomb to Honeycomb Networks and Superconductivity in LaPt$_x$Si$_{2-x}$","authors":"Sitaram Ramakrishnan, Tatsuya Yamakawa, Ryohei Oishi, Soichiro Yamane, Atsutoshi Ikeda, Masaki Kado, Yasuyuki Shimura, Toshiro Takabatake, Takahiro Onimaru, Yasuhiro Shibata, Arumugam Thamizhavel, Srinivasan Ramakrishnan, Shingo Yonezawa, Minoru Nohara","doi":"arxiv-2408.17033","DOIUrl":"https://doi.org/arxiv-2408.17033","url":null,"abstract":"We report the crystal structures and superconductivity (SC) of\u0000LaPt$_{x}$Si$_{2-x}$ ($0.5 leq x leq 1.0$) that are solid solutions of\u0000LaSi$_{2}$ and LaPtSi with centrosymmetric tetragonal ($I4_{1}/amd$,\u0000$D_{4h}^{19}$, #141) and non-centrosymmetric tetragonal ($I4_{1}md$,\u0000$C_{4v}^{11}$, #109) structures, respectively. It was found that at $0.86 leq\u0000x leq 1.00$, the non-centrosymmetric tetragonal symmetry is preserved, while\u0000partial disorder appears in alternating Pt and Si of the hyper-honeycomb\u0000network. The superconducting transition temperature $T_{rm c}$ was drastically\u0000reduced from 3.9 K to 1.5 K as $x$ varies from 1.0 to 0.86. Additionally, a\u0000hexagonal phase with an AlB$_{2}$-type structure ($P6/mmm$, $D_{6h}^{1}$,\u0000#191) has been discovered at $0.50 leq x leq 0.71$ with a honeycomb network\u0000of statistically distributed Pt and Si atoms. The hexagonal phase exhibited SC\u0000at $T_{rm c} = 0.38$ K. This system provides an opportunity to investigate the\u0000relationship between topological electronic states, SC, and disorders","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Superconductivity in pressurized Re$_{0.10}$Mo$_{0.90}$B$_2$ 加压 Re$_{0.10}$Mo$_{0.90}$B$_2$ 中的超导现象

arXiv - PHYS - Superconductivity Pub Date : 2024-08-30 DOI: arxiv-2408.17416

S. Sinha, J. Lim, Z. Li, J. S. Kim, A. C. Hire, P. M. Dee, R. S. Kumar, D. Popov, R. J. Hemley, R. G. Hennig, P. J. Hirschfeld, G. R. Stewart, J. J. Hamlin

引用次数: 0

Predicting topological invariants and unconventional superconducting pairing from density of states and machine learning 从态密度和机器学习预测拓扑不变性和非常规超导配对

arXiv - PHYS - Superconductivity Pub Date : 2024-08-29 DOI: arxiv-2408.16499

Flavio Noronha, Askery Canabarro, Rafael Chaves, Rodrigo G. Pereira

{"title":"Predicting topological invariants and unconventional superconducting pairing from density of states and machine learning","authors":"Flavio Noronha, Askery Canabarro, Rafael Chaves, Rodrigo G. Pereira","doi":"arxiv-2408.16499","DOIUrl":"https://doi.org/arxiv-2408.16499","url":null,"abstract":"Competition between magnetism and superconductivity can lead to\u0000unconventional and topological superconductivity. However, the experimental\u0000confirmation of the presence of Majorana edge states and unconventional pairing\u0000currently poses a major challenge. Here we consider a two-dimensional lattice\u0000model for a superconductor with spin-orbit coupling and exchange coupling to\u0000randomly distributed magnetic impurities. Depending on parameters of the model,\u0000this system may display topologically trivial or nontrivial edge states. We map\u0000out the phase diagram by computing the Bott index, a topological invariant\u0000defined in real space. We then use machine learning (ML) algorithms to predict\u0000the Bott index from the local density of states (LDOS) at zero energy,\u0000obtaining high-accuracy results. We also train ML models to predict the\u0000amplitude of odd-frequency pairing in the anomalous Green's function at zero\u0000energy. Once the ML models are trained using the LDOS, which is experimentally\u0000accessible via scanning tunneling spectroscopy, our method could be applied to\u0000predict the number of Majorana edge states and to estimate the magnitude of\u0000odd-frequency pairing in real materials.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Signatures of Amorphous Shiba State in FeTe$_{0.55}$Se$_{0.45}$ FeTe$_{0.55}$Se$_{0.45}$ 中非晶态芝态的特征

arXiv - PHYS - Superconductivity Pub Date : 2024-08-29 DOI: arxiv-2408.16598

Jinwon Lee, Sanghun Lee, Andreas Kreisel, Jens Paaske, Brian M. Andersen, Koen M. Bastiaans, Damianos Chatzopoulos, Genda Gu, Doohee Cho, Milan P. Allan

{"title":"Signatures of Amorphous Shiba State in FeTe$_{0.55}$Se$_{0.45}$","authors":"Jinwon Lee, Sanghun Lee, Andreas Kreisel, Jens Paaske, Brian M. Andersen, Koen M. Bastiaans, Damianos Chatzopoulos, Genda Gu, Doohee Cho, Milan P. Allan","doi":"arxiv-2408.16598","DOIUrl":"https://doi.org/arxiv-2408.16598","url":null,"abstract":"The iron-based superconductor FeTe$_{0.55}$Se$_{0.45}$ is a peculiar\u0000material: it hosts a surface state with a Dirac dispersion, is a putative\u0000topological superconductor hosting Majorana modes in vortices, and has an\u0000unusually low Fermi energy. The superconducting state is generally thought to\u0000be characterized by three gaps in different bands, with the usual homogenous,\u0000spatially extended Bogoliubov excitations -- in this work, we uncover evidence\u0000that it is instead of a very different nature. Our scanning tunneling\u0000spectroscopy data shows several peaks in the density of states above a full\u0000gap, and by analyzing the spatial and junction-resistance dependence of the\u0000peaks, we conclude that the peaks above the first one are not coherence peaks\u0000from different bands. Instead, comparisons with our simulations indicate that\u0000they originate from generalized Shiba states that are spatially overlapping.\u0000This can lead to an amorphous state of Bogoliubov quasiparticles, reminiscent\u0000of impurity bands in semiconductors. We discuss the origin and implications of\u0000this new state.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0