Surface superconductivity in the topological Weyl semimetal t-PtBi$_2$
Sebastian Schimmel, Yanina Fasano, Sven Hoffmann, Julia Besproswanny, Laura Teresa Corredor Bohorquez, Joaquín Puig, Bat-Chen Elshalem, Beena Kalisky, Grigory S… 展开作者
Sebastian Schimmel, Yanina Fasano, Sven Hoffmann, Julia Besproswanny, Laura Teresa Corredor Bohorquez, Joaquín Puig, Bat-Chen Elshalem, Beena Kalisky, Grigory Shipunov, Danny Baumann, Saicharan Aswartham, Bernd Büchner, Christian Hess
The advancement of quantum computation is eager on generating fault tolerant qubits, and topological superconductivity is a very promising concept for reaching this goal. Early experimental achievements study hybrid systems as well as doped intrinsic topological or superconducting materials presenting the phenomena at very low temperatures. However, higher critical temperatures are indispensable for technological exploitation. Promising very recent angle-resolved photoemission spectroscopy results reveal that superconductivity of the type-I Weyl semimetal trigonal PtBi$_2$ (t-PtBi$_2$) is located at the Fermi arcs surface states which renders t-PtBi$_2$ a candidate for intrinsic topological superconductivity. Here we show, using scanning tunnelling microscopy and spectroscopy (STM/STS) that t-PtBi$_2$ presents surface superconductivity at elevated temperatures (5 K). The gap magnitude is elusive: it is spatially inhomogeneous and spans from 0 to 20 meV. In particular, the large gap value and the shape of the quasiparticle excitation spectrum resemble the phenomenology of high-Tc superconductors. To our knowledge, this is the largest superconducting gap so far measured in a topological material. Moreover, we show that the superconducting state at 5 K persists up to 12 T magnetic field. Thus, we show that t-PtBi2 is a prime candidate for intrinsic topological superconductivity at technologically relevant temperatures, fields and gap magnitudes.
Atomic Visualization of Bulk and Surface Superconductivity in Weyl Semimetal γ-PtBi2
Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所）；School of Physical Sciences, University of Chinese Academy of Sciences（中国科学院大学物理科学学院）；Hefei National Laboratory（合肥国家实验室）；High Magnetic Field Laboratory, Chinese Academy of Sciences（中国科学院强磁场科学中心）
A minimal model for the Weyl nodes and Fermi arcs of PtBi$_2$
Centro Atómico Bariloche（巴里洛切原子中心）；Instituto Balseiro, CNEA（巴尔塞罗研究所，CNEA）；Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)（国家科学研究委员会）；Instituto de Nanociencia y Nanotecnología CNEA-CONICET（CNEA-CONICET纳米科学与技术研究所）
Surface-extended Andreev bound states emerging from intrinsic surface superconductivity of PtBi$_2$
Universität Würzburg（维尔茨堡大学）；Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area（粤港澳大湾区量子科学中心）；Bergische Universität Wuppertal（伍珀塔尔大学）；Leibniz-Institute for Solid State and Materials Research (IFW-Dresden)（德累斯顿固体与材料研究所）；Indian Institute of Science Education and Research（印度科学与教育研究所）；Technische Universität Dresden（德累斯顿工业大学）
Mechanism for Nodal Topological Superconductivity on PtBi$_2$ Surface
Institute for Theoretical Physics and Astrophysics, University of Würzburg（维尔茨堡大学理论物理与天体物理研究所）；Würzburg-Dresden Cluster of Excellence ctd.qmat（维尔茨堡-德累斯顿卓越集群ctd.qmat）
Tunable Chern superconductivity of PtBi$_2$ in slab geometry
Leibniz Institute for Solid State and Materials Research, IFW Dresden（德累斯顿莱布尼茨固体与材料研究所）；Würzburg-Dresden Cluster of Excellence ctd.qmat（维尔茨堡-德累斯顿卓越集群ctd.qmat）；Institute for Theoretical Physics, Technische Universität Dresden（德累斯顿工业大学理论物理研究所）
Topologically nontrivial superconducting phases have been engineered in topological materials by the proximity effect in contact with conventional superconductors. In this paper, by using the method of the Kronig-Penney model, we study the superconducting proximity effect in the bulk electronic states of Weyl semimetals by considering a multilayer structure consisting of Weyl-semimetal and superconductor layers. Due to the proximity effect, two Weyl nodes are decoupled into four nodes of Majorana fermions resulting in Weyl-superconductor phases or three-dimensional extension of topological-sup…
Probing bulk superconductivity in centrosymmetric Te-doped PtBi$_2$ single crystals
Leibniz Institute for Solid State and Materials Research（莱布尼茨固体和材料研究所）；Max Planck Institute for Chemical Physics of Solids（马克斯·普朗克固体化学物理研究所）；Centro Atómico Bariloche, CNEA-CONICET（巴里洛切原子中心，CNEA-CONICET）；B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine（乌克兰国家科学院B.维尔金低温物理与工程研究所）；Kyiv Academic University（基辅学术大学）
We have generalized a quasiclassical model for Weyl semimetals with a tilted band in the presence of an externally applied magnetic field. This model is applicable to ballistic, moderately disordered, and samples containing a high density of nonmagnetic impurities. We employ this formalism and show that a self-biased supercurrent, creating a ϕ0-junction, can flow through a triplet channel in Weyl semimetals. Furthermore, our results demonstrate that multiple supercurrent reversals are accessible through varying junction thickness and parameters characterizing Weyl semimetals. We discuss the in…
Disorder in Weyl semimetals and superconductors is surprisingly subtle, attracting attention and competing theories in recent years. In this brief review, we discuss the current theoretical understanding of the effects of short-ranged, quenched disorder on the low energy-properties of three-dimensional, topological Weyl semimetals and superconductors. We focus on the role of non-perturbative rare region effects on destabilizing the semimetal phase and rounding the expected semimetal-to-diffusive metal transition into a cross over. Furthermore, the consequences of disorder on the resulting natu…
