Superconducting properties and materials

  • Article
    | Open Access

    The pseudogap phase in cuprate superconductors is predicted to be a pair density wave state (PDW) but experimental evidence has been lacking. Here, the authors detect the temperature evolution of energy gap modulations and scattering interference signature suggesting the Bi2Sr2CaDyCu2O8 pseudogap phase contains a PDW.

    • Shuqiu Wang
    • , Peayush Choubey
    •  & J. C. Séamus Davis
  • Article
    | Open Access

    A space-time crystal (STC) is a nonequilibrium phase of matter displaying long-range order in both space and time. Here, the authors propose that the high-Tc cuprate superconductor Bi2Sr2CaCu2O8+x is a candidate of a classical discrete STC, when a parametric modulation periodic in time and uniform in space is applied.

    • Reinhold Kleiner
    • , Xianjing Zhou
    •  & Dafei Jin
  • Article
    | Open Access

    An enhanced superconducting pairing temperature (Tg) has only been observed in single-layer FeSe interfaced with TiOx system. Here, the authors construct a new interface composed of single-layer FeSe interfaced with LaFeO3 showing a highest Tg of 80 K among all-known interfacial superconductors.

    • Yuanhe Song
    • , Zheng Chen
    •  & Donglai Feng
  • Article
    | Open Access

    Strontium Ruthenate, Sr2RuO4, displays a remarkable number of intriguing physical phenomena, from superconductivity, to strain-induced ferromagnetism. Here, using low-energy muon spectroscopy, Fittipaldi et al. demonstrate the existence of unconventional magnetism at the surface of Sr2RuO4 in its normal state and without any applied strain.

    • R. Fittipaldi
    • , R. Hartmann
    •  & A. Di Bernardo
  • Article
    | Open Access

    Superconductivity reported in metals driven away from equilibrium via optical pumping has been proposed to arise from nonlinear coupling between electrons and optically excited phonons. The authors use an exact approach to show that here, disorder, which disfavors superconductivity, emerges even though the system is translationally invariant.

    • John Sous
    • , Benedikt Kloss
    •  & Andrew J. Millis
  • Article
    | Open Access

    Several hydrides have been observed high-Tc superconductivity under pressure, but a physical-chemical understanding of the properties enhancing Tc is still lacking. Here, the authors propose a magnitude named as networking value, combined with hydrogen fraction and the contribution of hydrogen to the density of states at Fermi level, can predict Tc of all hydrogen-based compounds with an accuracy of about 60 K.

    • Francesco Belli
    • , Trinidad Novoa
    •  & Ion Errea
  • Article
    | Open Access

    Superconductivity in FeSe attracted great interests to understand the mechanism of high temperature superconductivity. Here, the authors report a pressure induced superconductivity with a highest Tc of ~9 K in MnSe.

    • T. L. Hung
    • , C. H. Huang
    •  & T. K. Lee
  • Article
    | Open Access

    Van der Waals structures provide a new platform to explore novel physics of superconductor/ferromagnet interfaces. Here, NbSe2 Josephson junction with Cr2Ge2Te6 enables non-trivial Josephson phase by spin-dependent interaction, boosting the study of superconducting states with spin-orbit coupling and phase-controlled quantum electronic device.

    • H. Idzuchi
    • , F. Pientka
    •  & P. Kim
  • Article
    | Open Access

    The discovery of high temperature superconductivity in hydrogen-rich compounds stimulates further extensive studies. Here, the authors report superconductivity in pressurized yttrium-hydrogen system with highest predicted Tc among binary compounds.

    • Panpan Kong
    • , Vasily S. Minkov
    •  & Mikhail I. Eremets
  • Article
    | Open Access

    Whether the electronic nematicity is related to electronic pairing in strongly hole-doped iron-based superconductors remains controversial. Here, the authors perform transport measurements on AFe2As2 (A = K, Rb, Cs) superconductors under elastic strain, and find no indication of a nematic ordered state.

    • P. Wiecki
    • , M. Frachet
    •  & A. E. Böhmer
  • Article
    | Open Access

    Bound states in superconducting vortices are expected to exhibit an electron-hole asymmetry, but it is usually tiny and can be easily washed out. Here, the authors show that the vortex bound states coupling to magnetic impurities provides an axial electron-hole asymmetry on a much longer scale, and that the direction of the asymmetry depends on the band character of the superconducting material.

    • Sunghun Park
    • , Víctor Barrena
    •  & Hermann Suderow
  • Article
    | Open Access

    Understanding the strange metal behavior, characterized by linear-in-temperature resistivity, could shed light on the mechanism of unconventional superconductivity. Here, by using electrical resistivity measurements into the micro-Kelvin regime, the authors report evidence of unconventional superconductivity in the strange metal YbRh2Si2 and propose a possible pairing mechanism.

    • D. H. Nguyen
    • , A. Sidorenko
    •  & S. Paschen
  • Article
    | Open Access

    Despite the discovery of Majorana zero modes (MZM) in iron-based superconductors, sample inhomogeneity may destroy MZMs during braiding. Here, authors observe MZM in impurity-assisted vortices due to tuning of the bulk Dirac fermions in a homogeneous superconductor LiFeAs.

    • Lingyuan Kong
    • , Lu Cao
    •  & Hong Ding
  • Article
    | Open Access

    Two possible scenarios of the superconducting order parameter in Sr2RuO4 remain difficult to distinguish. Here, the authors observe that the onset temperature of time reversal symmetry breaking tracks the superconducting transition temperature in Sr2RuO4, supporting a dxz ± idyz order parameter.

    • Vadim Grinenko
    • , Debarchan Das
    •  & Rustem Khasanov
  • Article
    | Open Access

    Charge ordering and superconductivity are known to compete in layered cuprates; however, precise real-space characterization of their interplay has been lacking. Here, the authors address this using atomically-resolved cross-sectional scanning tunnelling microscopy and spectroscopy on cryogenically cleaved YBa2Cu3O6.81.

    • Chun-Chih Hsu
    • , Bo-Chao Huang
    •  & Ya-Ping Chiu
  • Article
    | Open Access

    The Hall effect has been used as a probe of the normal state of cuprates, when superconductivity is supressed by a magnetic field. Here, the authors report the vanishing of the Hall coefficient at high magnetic field in cuprates with stripe order and interpret it as a signature of the stripe-ordered phase.

    • Zhenzhong Shi
    • , P. G. Baity
    •  & Dragana Popović
  • Article
    | Open Access

    Superconductivity is often destroyed under magnetic field larger than a critical value called Pauli limit. Here, the authors report superconductivity beyond the Pauli limit in bulk single crystals of NbS2, suggesting the development of a Fulde-Ferrell-Larkin-Ovchinnikov state.

    • Chang-woo Cho
    • , Jian Lyu
    •  & Rolf Lortz
  • Article
    | Open Access

    Superconductivity often appears due to suppression of competing electronic orders. Here, the authors present a contrary example showing a superconducting dome inside the parent phase with a stripe charge order in IrTe2 nanoflakes and identify their unusual superconducting properties.

    • Sungyu Park
    • , So Young Kim
    •  & Jun Sung Kim
  • Article
    | Open Access

    Here, Pelliciari et al. present resonant inelastic X-ray scattering on monolayer samples of unconventional superconductor FeSe, finding evidence for gapped and dispersionless spin excitations. These experiments are very difficult due to the extremely small scattering volume of the FeSe monolayer.

    • Jonathan Pelliciari
    • , Seher Karakuzu
    •  & Riccardo Comin
  • Article
    | Open Access

    Previous work on critical scaling at the superconductor-to-insulator transition has shown variations across different materials. Here, the authors use a space charge doping technique to tune the transition in a single layer cuprate sample and present evidence of the universal scaling behaviour.

    • Fang Wang
    • , Johan Biscaras
    •  & Abhay Shukla
  • Article
    | Open Access

    Topological superconductors are potentially important for future quantum computation, but they are very rare in nature. Here, the authors observe topological surface states acquiring a nodeless superconducting gap with similar magnitude as that of the bulk states in 2M-WS2, suggesting an intrinsic topological superconductor.

    • Y. W. Li
    • , H. J. Zheng
    •  & Y. L. Chen
  • Article
    | Open Access

    Background radiation has been identified as a key factor limiting the coherence times of superconducting circuits. Here, the authors measure the impact of environmental and cosmic radiation on a superconducting resonator with varying degrees of shielding, including an underground facility.

    • L. Cardani
    • , F. Valenti
    •  & I. M. Pop
  • Article
    | Open Access

    A recent report on electrostatic field effect in superconducting devices provides a high potential for advanced quantum technology, but it remains controversial. Here, the authors report that the suppression of critical current, which was attributed to the field effect, can instead be explained by quasiparticle excitations in the constriction of superconducting devices.

    • I. Golokolenov
    • , A. Guthrie
    •  & V. Tsepelin
  • Article
    | Open Access

    Chiral superconductors are predicted to realize Majorana normal fluid at its boundary, but remain elusive experimentally. Here, Bae et al. report anomalous surface normal fluid response in UTe2 single crystal which is further attributed to a chiral spin-triplet pairing state.

    • Seokjin Bae
    • , Hyunsoo Kim
    •  & Steven M. Anlage
  • Article
    | Open Access

    A superconducting diode is dissipationless and desirable for electronic circuits with ultralow power consumption, yet it remains challenging to realize it. Here, the authors achieve a superconducting diode in a conventional superconducting film patterned with a conformal array of nanoscale holes.

    • Yang-Yang Lyu
    • , Ji Jiang
    •  & Wai-Kwong Kwok
  • Article
    | Open Access

    Chiral superconductors are very rare topological materials. Here, the authors report spontaneous magnetic fields inside the superconducting state and low temperature linear behavior in the superfluid density in LaPt3P, suggesting a chiral d-wave singlet superconducting state.

    • P. K. Biswas
    • , S. K. Ghosh
    •  & M. R. Lees
  • Article
    | Open Access

    The discovery of a new two-dimensional van der Waals layered MoSi2N4 material inspires many attentions. Here, the authors report intercalation strategies to explore a much wider range of MA2Z4 family and predict amount of materials accessible to experimental verifications with emergent topological, magnetic or Ising superconductivity properties.

    • Lei Wang
    • , Yongpeng Shi
    •  & Xing-Qiu Chen
  • Article
    | Open Access

    The relation between enhanced superconductivity in monolayer FeSe grown on SrTiO3 and the large nematicity in multilayer FeSe on SrTiO3 remains not well understood. Here, the authors observe a long-range smectic phase in bilayer FeSe films but vanishes in monolayer FeSe, providing a new instability to help enhance the superconductivity.

    • Yonghao Yuan
    • , Xuemin Fan
    •  & Wei Li
  • Article
    | Open Access

    Compton scattering provides information on the Fermi surface (FS) hence very useful to understand the electronic structure of high temperature superconductors. Here, Yamase et al. perform Compton scattering measurements on La2−xSrxCuO4 samples and observe deformed FS in CuO2 plane due to nematicity but recovering fourfold symmetry in bulk FS.

    • Hiroyuki Yamase
    • , Yoshiharu Sakurai
    •  & Kazuyoshi Yamada
  • Article
    | Open Access

    The influence of spin-orbit coupling on the hybridization of Shiba states in dimers of magnetic atoms on superconducting surfaces remains unexplored. Here, the authors reveal a splitting of atomic Shiba orbitals due to spin-orbit coupling and broken inversion symmetry in antiferromagnetically coupled Mn dimers placed on a Nb(110) surface.

    • Philip Beck
    • , Lucas Schneider
    •  & Roland Wiesendanger
  • Article
    | Open Access

    Quantum computers based on superconducting transmon qubits are limited by single qubit lifetimes and coherence times, which are orders of magnitude shorter than limits imposed by bulk material properties. Here, the authors fabricate two-dimensional transmon qubits with both lifetimes and coherence times longer than 0.3 milliseconds by replacing niobium with tantalum in the device.

    • Alexander P. M. Place
    • , Lila V. H. Rodgers
    •  & Andrew A. Houck
  • Article
    | Open Access

    The discovery of superconductivity in metal hydrides requires an understanding of hydrogen interactions with the heavy atom sublattice under high pressure. Here, the authors report evidence of a strong effect of hydrogen on the density increase of 4d yttrium states and strong anharmonic vibrations of yttrium atoms in YH3.

    • J. Purans
    • , A. P. Menushenkov
    •  & M. I. Eremets
  • Article
    | Open Access

    The optical response of a clean momentum-conserved conventional superconductor is known to be forbidden. Here, Ahn and Nagaosa propose three conditions that intrinsic optical excitations can occur in clean multi-band superconductors by satisfying one of the three.

    • Junyeong Ahn
    •  & Naoto Nagaosa
  • Article
    | Open Access

    The effect of Rashba spin orbit coupling (SOC) on superconductivity remains elusive. Here, the authors report largely enhanced in-plane upper critical magnetic field due to Rashba SOC induced dynamic spin-momentum locking on the surfaces of an atomic-layer superconductor.

    • Shunsuke Yoshizawa
    • , Takahiro Kobayashi
    •  & Takashi Uchihashi
  • Article
    | Open Access

    Understanding the relation of different electronic orders in high temperature superconductors is of fundamental interest. Here, the authors observe a checkerboard charge order along [110] direction of FeSe.

    • Kunliang Bu
    • , Wenhao Zhang
    •  & Yi Yin
  • Article
    | Open Access

    How a Mott insulating state evolves into a conducting or superconducting state is a central issue in doping a Mott insulator and important to understand the physics in high temperature cuprate superconductors. Here, the authors visualize the electronic structure evolution of a Mott insulator within the full Mott gap region and address the fundamental issues.

    • Cheng Hu
    • , Jianfa Zhao
    •  & X. J. Zhou
  • Article
    | Open Access

    Braiding Majorana modes is essential for topological quantum computing, but it remains difficult to find a suitable platform. Here, the authors report the evidence of hybridization between field-induced and magnetic adatom induced Majorana modes in an iron-based superconductor FeTe0.55Se0.45, providing a possible single-material platform for braiding Majorana modes.

    • Peng Fan
    • , Fazhi Yang
    •  & Hong-Jun Gao
  • Article
    | Open Access

    A recent finding of tuning critical current in metallic nanowires by application of small gate voltages seems at odds with general understanding. Here, Ritter et al. study similar nanowires and link the origin of the critical current suppression to tunneling of few high-energy electrons between gate and nanowire, ruling out direct tuning by electric fields.

    • M. F. Ritter
    • , A. Fuhrer
    •  & F. Nichele
  • Article
    | Open Access

    The impact of local magnetic impurities on superconducting order parameter remains largely unexplored. Here, the authors visualize the effect of different magnetic perturbations on a superconductor, unveiling a rich correlation of the interplay between quantum spins and superconductivity in different spectroscopic regimes.

    • Felix Küster
    • , Ana M. Montero
    •  & Paolo Sessi
  • Article
    | Open Access

    Josephson coupling determines the superconducting phase stiffness and sets the energy scale of plasma waves. Here, the authors show that THz light can induce two-plasmon excitations of both out-of-plane and in-plane phase modes, leading however to markedly different resonant and thermal effects due to the strong anisotropy of the Josephson couplings.

    • Francesco Gabriele
    • , Mattia Udina
    •  & Lara Benfatto
  • Article
    | Open Access

    Knowledge of effective Coulomb interactions is central to understand emergent quantum phases in strongly correlated systems. Here, Boschini et al. report a dynamic quasi-circular spectrum of charge density wave fluctuations in the CuO2 plane of Bi2Sr2CaCu2O8+δ, shedding a light on understanding how Coulomb interactions can lead to rotational and translational symmetry breaking in the cuprates.

    • F. Boschini
    • , M. Minola
    •  & E. H. da Silva Neto
  • Article
    | Open Access

    Despite striking progress in promoting Majorana physics to topological quantum computation, there are many disadvantages in existing material platforms. Here, Papaj and Fu propose a new two-dimensional system for realization of Majorana physics based on a segmented Fermi surface due to the interplay between superconductivity and magnetic field.

    • Michał Papaj
    •  & Liang Fu