KeYuan Ma, Subhajit Roychowdhury, Jonathan Noky, Horst Borrmann, Walter Schnelle, Chandra Shekhar, Sergey A. Medvedev, Claudia Felser
RhBi$_2$ is a polymorphic system that exhibits two distinct phases. RhBi$_2$ in the triclinic phase has been identified as a weak topological insulator with a van Hove singularity point close to the Fermi energy. Thus, triclinic RhBi$_2$ is expected to exhibit exotic quantum properties under strain or pressure. In this study, we report on the emergence of superconductivity in the monoclinic RhBi$_2$ under external pressures. The electrical resistivity behavior of the monoclinic RhBi$_2$ single crystal is studied at a wide range of applied external pressures up to 40 GPa. We observe a pressure-induced superconductivity with a dome-shaped dependence of the critical temperature on pressure at pressures above 10 GPa. A maximum critical temperature ($T_mathrm{c}$) value of $T_mathrm{c}$ = 5.1 K is reached at the pressure of 16.1 GPa. Furthermore, we performed detailed ab initio calculations to understand the electronic band structures of monoclinic RhBi$_2$ under varying pressures. The combination of topology and pressure-induced superconductivity in the RhBi$_2$ polymorphic system may provide us with a new promising material platform to investigate topological superconductivity.
{"title":"Pressure-induced superconductivity in monoclinic RhBi$_2$","authors":"KeYuan Ma, Subhajit Roychowdhury, Jonathan Noky, Horst Borrmann, Walter Schnelle, Chandra Shekhar, Sergey A. Medvedev, Claudia Felser","doi":"arxiv-2409.06358","DOIUrl":"https://doi.org/arxiv-2409.06358","url":null,"abstract":"RhBi$_2$ is a polymorphic system that exhibits two distinct phases. RhBi$_2$\u0000in the triclinic phase has been identified as a weak topological insulator with\u0000a van Hove singularity point close to the Fermi energy. Thus, triclinic\u0000RhBi$_2$ is expected to exhibit exotic quantum properties under strain or\u0000pressure. In this study, we report on the emergence of superconductivity in the\u0000monoclinic RhBi$_2$ under external pressures. The electrical resistivity\u0000behavior of the monoclinic RhBi$_2$ single crystal is studied at a wide range\u0000of applied external pressures up to 40 GPa. We observe a pressure-induced\u0000superconductivity with a dome-shaped dependence of the critical temperature on\u0000pressure at pressures above 10 GPa. A maximum critical temperature\u0000($T_mathrm{c}$) value of $T_mathrm{c}$ = 5.1 K is reached at the pressure of\u000016.1 GPa. Furthermore, we performed detailed ab initio calculations to\u0000understand the electronic band structures of monoclinic RhBi$_2$ under varying\u0000pressures. The combination of topology and pressure-induced superconductivity\u0000in the RhBi$_2$ polymorphic system may provide us with a new promising material\u0000platform to investigate topological superconductivity.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209990","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}
We study the intravalley spin-polarized superconductivity in rhombohedral tetralayer graphene, which has been discovered experimentally in Han $et$ $al$ arXiv:2408.15233. We construct a minimal model for the intravalley spin-polarized superconductivity, assuming a simplified anisotropic interaction that depends only on the angle between the incoming and outgoing momenta. Despite the absence of Fermi surface nesting, we show that the superconductivity appears near the Van Hove singularity with the maximal $T_c$ near a bifurcation point of the peaks in the density of states. We identify the topological $p+ip$, topological $h+ih$, and the non-topological nodal $f$-wave pairings as the possible states, which are all pair density wave orders due to the intravalley nature. Furthermore, these pair density wave orders require a finite attractive threshold for superconductivity, resulting in narrow superconducting regions, consistent with experimental findings. We discuss the possible pairing mechanisms and point out that the Kohn-Luttinger mechanism is a plausible explanation for the intravalley spin-polarized superconductivity in the rhombohedral tetralayer graphene.
{"title":"Intravalley spin-polarized superconductivity in rhombohedral tetralayer graphene","authors":"Yang-Zhi Chou, Jihang Zhu, Sankar Das Sarma","doi":"arxiv-2409.06701","DOIUrl":"https://doi.org/arxiv-2409.06701","url":null,"abstract":"We study the intravalley spin-polarized superconductivity in rhombohedral\u0000tetralayer graphene, which has been discovered experimentally in Han $et$ $al$\u0000arXiv:2408.15233. We construct a minimal model for the intravalley\u0000spin-polarized superconductivity, assuming a simplified anisotropic interaction\u0000that depends only on the angle between the incoming and outgoing momenta.\u0000Despite the absence of Fermi surface nesting, we show that the\u0000superconductivity appears near the Van Hove singularity with the maximal $T_c$\u0000near a bifurcation point of the peaks in the density of states. We identify the\u0000topological $p+ip$, topological $h+ih$, and the non-topological nodal $f$-wave\u0000pairings as the possible states, which are all pair density wave orders due to\u0000the intravalley nature. Furthermore, these pair density wave orders require a\u0000finite attractive threshold for superconductivity, resulting in narrow\u0000superconducting regions, consistent with experimental findings. We discuss the\u0000possible pairing mechanisms and point out that the Kohn-Luttinger mechanism is\u0000a plausible explanation for the intravalley spin-polarized superconductivity in\u0000the rhombohedral tetralayer graphene.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209988","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}
Chuyi Tuo, Ming-Rui Li, Zhengzhi Wu, Wen Sun, Hong Yao
Since the very recent discovery of unconventional superconductivity in twisted WSe${}_{2}$ homobilayers at filling $nu=-1$, considerable interests arise in revealing its mechanism. In this paper, we developed a three-band tight-binding model with non-trivial band topology by direct Wannierization of the low-energy continuum model. Incorporating both onsite Hubbard repulsion and next-nearest-neighbor attraction, we then performed a mean-field analysis of the microscopic model and obtained a phase diagram qualitatively consistent with the experiment results. For zero or weak displacement field, the ground state is a Chern number $C=pm 2$ topological superconductor in the Altland-Zirnbauer A-class (breaking time-reversal but preserving total $S_z$ symmetry) with inter-valley pairing dominant in $d_{xy}mp id_{x^2-y^2}$-wave (mixing with a subdominant $p_xpm i p_y$-wave) component. For a relatively strong displacement field, the ground state is a correlated insulator with $120^circ$ antiferromagnetic order. Our results provide new insights into the nature of the twisted WSe${}_{2}$ systems and suggest the need for further theoretical and experimental explorations.
{"title":"Theory of Topological Superconductivity and Antiferromagnetic Correlated Insulators in Twisted Bilayer WSe${}_2$","authors":"Chuyi Tuo, Ming-Rui Li, Zhengzhi Wu, Wen Sun, Hong Yao","doi":"arxiv-2409.06779","DOIUrl":"https://doi.org/arxiv-2409.06779","url":null,"abstract":"Since the very recent discovery of unconventional superconductivity in\u0000twisted WSe${}_{2}$ homobilayers at filling $nu=-1$, considerable interests\u0000arise in revealing its mechanism. In this paper, we developed a three-band\u0000tight-binding model with non-trivial band topology by direct Wannierization of\u0000the low-energy continuum model. Incorporating both onsite Hubbard repulsion and\u0000next-nearest-neighbor attraction, we then performed a mean-field analysis of\u0000the microscopic model and obtained a phase diagram qualitatively consistent\u0000with the experiment results. For zero or weak displacement field, the ground\u0000state is a Chern number $C=pm 2$ topological superconductor in the\u0000Altland-Zirnbauer A-class (breaking time-reversal but preserving total $S_z$\u0000symmetry) with inter-valley pairing dominant in $d_{xy}mp id_{x^2-y^2}$-wave\u0000(mixing with a subdominant $p_xpm i p_y$-wave) component. For a relatively\u0000strong displacement field, the ground state is a correlated insulator with\u0000$120^circ$ antiferromagnetic order. Our results provide new insights into the\u0000nature of the twisted WSe${}_{2}$ systems and suggest the need for further\u0000theoretical and experimental explorations.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209987","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}
Rais S. Shaikhaidarov, Kyung Ho Kim, Jacob Dunstan, Ilya Antonov, Dmitry Golubev, Vladimir N Antonov, Oleg V Astafiev
Synchronization of Bloch oscillations in small Josephson junctions (JJs) under microwave radiation, which leads to current quantization, has been proposed as an effect that is dual to the appearance of Shapiro steps. This current quantization was recently demonstrated in superconducting nanowires in a compact high-impedance environment. Direct observation of current quantization in JJs would cofirm the synchronization of Bloch oscillations with microwaves and help with the realisation of the metrological current standard. Here, we place JJs in a high-impedance environment and demonstrate dual Shapiro steps for frequencies up to 24 GHz (I=7.7 nA). Current quantization exists, however, only in a narrow range of JJ parameters. We carry out a systematic study to explain this by invoking the model of a JJ in the presence of thermal noise. The findings are important for fundamental physics and application in quantum metrology.
{"title":"Quantized current steps due to the synchronization of microwaves with Bloch oscillations in small Josephson junctions","authors":"Rais S. Shaikhaidarov, Kyung Ho Kim, Jacob Dunstan, Ilya Antonov, Dmitry Golubev, Vladimir N Antonov, Oleg V Astafiev","doi":"arxiv-2409.05707","DOIUrl":"https://doi.org/arxiv-2409.05707","url":null,"abstract":"Synchronization of Bloch oscillations in small Josephson junctions (JJs)\u0000under microwave radiation, which leads to current quantization, has been\u0000proposed as an effect that is dual to the appearance of Shapiro steps. This\u0000current quantization was recently demonstrated in superconducting nanowires in\u0000a compact high-impedance environment. Direct observation of current\u0000quantization in JJs would cofirm the synchronization of Bloch oscillations with\u0000microwaves and help with the realisation of the metrological current standard.\u0000Here, we place JJs in a high-impedance environment and demonstrate dual Shapiro\u0000steps for frequencies up to 24 GHz (I=7.7 nA). Current quantization exists,\u0000however, only in a narrow range of JJ parameters. We carry out a systematic\u0000study to explain this by invoking the model of a JJ in the presence of thermal\u0000noise. The findings are important for fundamental physics and application in\u0000quantum metrology.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209991","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}
We report superconductivity in the ternary compound IrBi$_{0.8}$Te$_{1.2}$ with critical temperature 1.7 K. The replacement of Bi by Te leads to the metallic conductivity in contrast to the semiconducting parent compound IrBiTe. The superconductivity can be further enhanced by application of external pressure. $T_c$ demonstrates dome-shaped dependence on pressure with a maximum value of 2.6 K at 26.5 GPa. Pressure effects on electronic properties and lattice dynamic of IrBi$_{0.8}$Te$_{1.2}$ were studied by pressure dependent electrical resistivity, Hall effect and Raman spectroscopy measurements.
{"title":"Superconductivity in ternary pyrite-type compound IrBi$_{1-x}$Te$_{1+x}$ ($x approx 0.2$) at ambient and high pressure","authors":"Qing-Ge Mu, Walter Schnelle, Guo-Wei Li, Horst Bormann, Claudia Felser, Sergey Medvedev","doi":"arxiv-2409.05649","DOIUrl":"https://doi.org/arxiv-2409.05649","url":null,"abstract":"We report superconductivity in the ternary compound IrBi$_{0.8}$Te$_{1.2}$\u0000with critical temperature 1.7 K. The replacement of Bi by Te leads to the\u0000metallic conductivity in contrast to the semiconducting parent compound IrBiTe.\u0000The superconductivity can be further enhanced by application of external\u0000pressure. $T_c$ demonstrates dome-shaped dependence on pressure with a maximum\u0000value of 2.6 K at 26.5 GPa. Pressure effects on electronic properties and\u0000lattice dynamic of IrBi$_{0.8}$Te$_{1.2}$ were studied by pressure dependent\u0000electrical resistivity, Hall effect and Raman spectroscopy measurements.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210174","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}
C. Fohn, D. Wander, D. Nikolic, S. Garaudée, H. Courtois, W. Belzig, C. Chapelier, V. Renard, C. B. Winkelmann
We investigate superconducting gallium in its $alpha$ phase using scanning tunneling microscopy and spectroscopy at temperatures down to about 100 mK. High-resolution tunneling spectroscopies using both superconducting and normal tips show that superconducting $alpha$-Ga is accurately described by Bardeen-Cooper-Schrieffer theory, with a gap $Delta_{rm Ga}$ = 163 $mu$eV on the $alpha-$Ga(112) facet, with highly homogeneous spectra over the surface, including atomic defects and step edges. Using a superconducting Pb tip, we furthermore study the low-bias conductance features of the Josephson junction formed between tip and sample. The features are accurately described by dynamical Coulomb blockade theory, highlighting $alpha-$Ga as a possible platform for surface science studies of mesoscopic superconductivity.
{"title":"Superconductivity of alpha-gallium probed on the atomic scale by normal and Josephson tunneling","authors":"C. Fohn, D. Wander, D. Nikolic, S. Garaudée, H. Courtois, W. Belzig, C. Chapelier, V. Renard, C. B. Winkelmann","doi":"arxiv-2409.05758","DOIUrl":"https://doi.org/arxiv-2409.05758","url":null,"abstract":"We investigate superconducting gallium in its $alpha$ phase using scanning\u0000tunneling microscopy and spectroscopy at temperatures down to about 100 mK.\u0000High-resolution tunneling spectroscopies using both superconducting and normal\u0000tips show that superconducting $alpha$-Ga is accurately described by\u0000Bardeen-Cooper-Schrieffer theory, with a gap $Delta_{rm Ga}$ = 163 $mu$eV on\u0000the $alpha-$Ga(112) facet, with highly homogeneous spectra over the surface,\u0000including atomic defects and step edges. Using a superconducting Pb tip, we\u0000furthermore study the low-bias conductance features of the Josephson junction\u0000formed between tip and sample. The features are accurately described by\u0000dynamical Coulomb blockade theory, highlighting $alpha-$Ga as a possible\u0000platform for surface science studies of mesoscopic superconductivity.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210182","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}
T. Adachi, T. Ogawa, Y. Komiyama, T. Sumura, Y. Saito-Tsuboi, T. Takeuchi, K. Mano, K. Manabe, K. Kawabata, T. Imazu, A. Koda, W. Higemoto, H. Okabe, J. G. Nakamura, T. U. Ito, R. Kadono, C. Baines, I. Watanabe, Y. Imai, J. Goryo, M. Nohara, K. Kudo
Chiral superconductivity exhibits the formation of novel electron pairs that breaks the time-reversal symmetry and has been actively studied in various quantum materials in recent years. However, despite its potential to provide definitive information, effects of disorder in the crystal structure on the chiral superconductivity has not yet been clarified, and therefore the investigation using a solid-solution system is desirable. We report muon-spin-relaxation (muSR) results of layered pnictide BaPtAs_1-x_Sb_x_ with a honeycomb network composed of Pt and (As, Sb). We observed an increase of the zero-field muon-spin relaxation rate in the superconducting (SC) state at the Sb end of x=1.0, suggesting the occurrence of spontaneous magnetic field due to the time-reversal symmetry breaking in the SC state. On the other hand, spontaneous magnetic field was almost and completely suppressed for the As-Sb mixed samples of x=0.9 and 0.2, respectively, suggesting that the time-reversal symmetry breaking SC state in x=1.0 is sensitive to disorder. The magnetic penetration depth estimated from transverse-field muSR measurements at x=1.0 and 0.2 behaved like weak-coupling s-wave superconductivity. These seemingly incompatible zero-field and transverse-field muSR results of BaPtAs_1-x_Sb_x_ with x=1.0 could be understood in terms of chiral d-wave superconductivity with point nodes on the three-dimensional Fermi surface.
{"title":"Spontaneous magnetic field and disorder effects in BaPtAs_1-x_Sb_x_ with honeycomb network","authors":"T. Adachi, T. Ogawa, Y. Komiyama, T. Sumura, Y. Saito-Tsuboi, T. Takeuchi, K. Mano, K. Manabe, K. Kawabata, T. Imazu, A. Koda, W. Higemoto, H. Okabe, J. G. Nakamura, T. U. Ito, R. Kadono, C. Baines, I. Watanabe, Y. Imai, J. Goryo, M. Nohara, K. Kudo","doi":"arxiv-2409.05266","DOIUrl":"https://doi.org/arxiv-2409.05266","url":null,"abstract":"Chiral superconductivity exhibits the formation of novel electron pairs that\u0000breaks the time-reversal symmetry and has been actively studied in various\u0000quantum materials in recent years. However, despite its potential to provide\u0000definitive information, effects of disorder in the crystal structure on the\u0000chiral superconductivity has not yet been clarified, and therefore the\u0000investigation using a solid-solution system is desirable. We report\u0000muon-spin-relaxation (muSR) results of layered pnictide BaPtAs_1-x_Sb_x_ with a\u0000honeycomb network composed of Pt and (As, Sb). We observed an increase of the\u0000zero-field muon-spin relaxation rate in the superconducting (SC) state at the\u0000Sb end of x=1.0, suggesting the occurrence of spontaneous magnetic field due to\u0000the time-reversal symmetry breaking in the SC state. On the other hand,\u0000spontaneous magnetic field was almost and completely suppressed for the As-Sb\u0000mixed samples of x=0.9 and 0.2, respectively, suggesting that the time-reversal\u0000symmetry breaking SC state in x=1.0 is sensitive to disorder. The magnetic\u0000penetration depth estimated from transverse-field muSR measurements at x=1.0\u0000and 0.2 behaved like weak-coupling s-wave superconductivity. These seemingly\u0000incompatible zero-field and transverse-field muSR results of BaPtAs_1-x_Sb_x_\u0000with x=1.0 could be understood in terms of chiral d-wave superconductivity with\u0000point nodes on the three-dimensional Fermi surface.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210173","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}
We review the theoretical model underpinning the recently reported room-temperature, ambient-pressure superconductivity along line defects on the surface of highly-oriented pyrolytic graphite. The main ingredients for this 1D room-temperature superconductivity are pairing by effective strain gauge fields, the formation of an effective Josephson junction array in its Bose metal state on the surface and the suppression of phase slips by dimensional embedding in an extremely well-conducting 3D bulk structure.
{"title":"Room-temperature superconductivity in 1D","authors":"Carlo A. Trugenberger","doi":"arxiv-2409.05031","DOIUrl":"https://doi.org/arxiv-2409.05031","url":null,"abstract":"We review the theoretical model underpinning the recently reported\u0000room-temperature, ambient-pressure superconductivity along line defects on the\u0000surface of highly-oriented pyrolytic graphite. The main ingredients for this 1D\u0000room-temperature superconductivity are pairing by effective strain gauge\u0000fields, the formation of an effective Josephson junction array in its Bose\u0000metal state on the surface and the suppression of phase slips by dimensional\u0000embedding in an extremely well-conducting 3D bulk structure.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210176","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}
Chenghao Shen, Jong E. Han, Thomas Vezin, Mohammad Alidoust, Igor Žutić
While spin-triplet pairing remains elusive in nature, there is a growing effort to realize proximity-induced equal-spin triplet superconductivity in junctions with magnetic regions or an applied magnetic field and common $s$-wave superconductors. To enhance such spin-triplet contribution, it is expected that junctions with a weak interfacial barrier and strong spin-orbit coupling are desirable. Intuitively, a weak interfacial barrier enables a robust proximity-induced superconductivity and strong spin-orbit coupling promotes spin mixing, converting spin-singlet into spin-triplet superconductivity. In contrast, we reveal a nonmonotonic spin-triplet contribution with the strength of the interfacial barrier and spin-orbit coupling. This picture is established by considering different signatures in conductance and superconducting correlations, as well as by performing self-consistent calculations. As a result, we identify a strongly enhanced spin-triplet superconductivity, realized for an intermediate strength of interfacial barrier and spin-orbit coupling. In junctions with magnetic regions, an enhanced spin-triplet superconductivity leads to a large magnetoanisotropy of conductance and superconducting correlations. This picture of an enhanced spin-triplet superconductivity is consistent with experiments demonstrating a huge increase in the conductance magnetoanisotropy, which we predict can be further enhanced at a finite bias.
{"title":"Signatures of enhanced spin-triplet superconductivity induced by interfacial properties","authors":"Chenghao Shen, Jong E. Han, Thomas Vezin, Mohammad Alidoust, Igor Žutić","doi":"arxiv-2409.04943","DOIUrl":"https://doi.org/arxiv-2409.04943","url":null,"abstract":"While spin-triplet pairing remains elusive in nature, there is a growing\u0000effort to realize proximity-induced equal-spin triplet superconductivity in\u0000junctions with magnetic regions or an applied magnetic field and common\u0000$s$-wave superconductors. To enhance such spin-triplet contribution, it is\u0000expected that junctions with a weak interfacial barrier and strong spin-orbit\u0000coupling are desirable. Intuitively, a weak interfacial barrier enables a\u0000robust proximity-induced superconductivity and strong spin-orbit coupling\u0000promotes spin mixing, converting spin-singlet into spin-triplet\u0000superconductivity. In contrast, we reveal a nonmonotonic spin-triplet\u0000contribution with the strength of the interfacial barrier and spin-orbit\u0000coupling. This picture is established by considering different signatures in\u0000conductance and superconducting correlations, as well as by performing\u0000self-consistent calculations. As a result, we identify a strongly enhanced\u0000spin-triplet superconductivity, realized for an intermediate strength of\u0000interfacial barrier and spin-orbit coupling. In junctions with magnetic\u0000regions, an enhanced spin-triplet superconductivity leads to a large\u0000magnetoanisotropy of conductance and superconducting correlations. This picture\u0000of an enhanced spin-triplet superconductivity is consistent with experiments\u0000demonstrating a huge increase in the conductance magnetoanisotropy, which we\u0000predict can be further enhanced at a finite bias.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210180","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}
Quasiparticle relaxation in pure superconductors is thought to be determined by the intrinsic inelastic scattering rate in the material. In certain applications, i.e. superconducting qubits and circuits, excess quasiparticles exist at densities far beyond the thermal equilibrium level, potentially leading to dephasing and energy loss. In order to engineer superconductors with shorter overall quasiparticle lifetimes, we consider the impact of a proximity layer on the transport of quasiparticles in a superconductor. We find that a normal metal layer can be used to significantly increase the relaxation rate of quasiparticles in a superconductor, as seen by a large reduction in the quasiparticle charge imbalance in a fully proximitized Cu/Al bilayer wire. The mechanism for this effect may be useful for preventing quasiparticle poisoning of qubits using carefully chosen proximity bilayers consisting of clean superconductors and disordered normal metals.
{"title":"Enhanced Quasiparticle Relaxation in a Superconductor via the Proximity Effect","authors":"Kevin M. Ryan, Venkat Chandrasekhar","doi":"arxiv-2409.05233","DOIUrl":"https://doi.org/arxiv-2409.05233","url":null,"abstract":"Quasiparticle relaxation in pure superconductors is thought to be determined\u0000by the intrinsic inelastic scattering rate in the material. In certain\u0000applications, i.e. superconducting qubits and circuits, excess quasiparticles\u0000exist at densities far beyond the thermal equilibrium level, potentially\u0000leading to dephasing and energy loss. In order to engineer superconductors with\u0000shorter overall quasiparticle lifetimes, we consider the impact of a proximity\u0000layer on the transport of quasiparticles in a superconductor. We find that a\u0000normal metal layer can be used to significantly increase the relaxation rate of\u0000quasiparticles in a superconductor, as seen by a large reduction in the\u0000quasiparticle charge imbalance in a fully proximitized Cu/Al bilayer wire. The\u0000mechanism for this effect may be useful for preventing quasiparticle poisoning\u0000of qubits using carefully chosen proximity bilayers consisting of clean\u0000superconductors and disordered normal metals.","PeriodicalId":501069,"journal":{"name":"arXiv - PHYS - Superconductivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210175","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}
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