Article
Multidisciplinary Sciences
Chuang Li, Xun-Jiang Luo, Li Chen, Dong E. Liu, Fu-Chun Zhang, Xin Liu
Summary: In this study, an iron-based superconducting nanowire system is proposed as a platform to manipulate Majorana zero modes (MZMs) and reveal their non-Abelian braiding statistics in a broad topological nontrivial parameter space.
NATIONAL SCIENCE REVIEW
(2022)
Article
Multidisciplinary Sciences
Marco Valentini, Maksim Borovkov, Elsa Prada, Sara Marti-Sanchez, Marc Botifoll, Andrea Hofmann, Jordi Arbiol, Ramon Aguado, Pablo San-Jose, Georgios Katsaros
Summary: Hybrid semiconductor-superconductor devices have great potential for realizing topological quantum computing with Majorana zero modes. However, the detection of Majorana modes based on either tunnelling or Coulomb blockade spectroscopy is still disputable. In this study, we propose an experimental protocol that allows us to perform both types of measurement on the same hybrid island, effectively reducing ambiguities in Majorana detections.
Article
Nanoscience & Nanotechnology
Xuejing Wang, Sean M. Thomas, J. Kevin Baldwin, Sadhvikas Addamane, Chris Sheehan, Jinkyoung Yoo
Summary: Novel heterostructures formed by coupling one-dimensional semiconductor nanowires and superconducting thin films have great potential for next-generation quantum computing. In this study, high-crystalline SiGe nanowires were grown on a NbTiN thin film, resulting in an Ohmic heterostructure with a shifted superconducting transition temperature (T(c)). The atomic-resolution characterization showed a sharp SiGe/NbTiN interface without atomic interdiffusion. X-ray diffraction experiments suggested a potential preferred d-spacing matching between (200) NbTiN and (110) SiGe grains. The observed out-of-plane compressive strain within the NbTiN films, along with the SiGe nanowires, explained the downward shift in superconductivity behavior. These findings provide scientific insights into functional heterostructures formed by coupling multi-dimensional materials, which could enable tunable superconductivity for quantum science applications.
Article
Materials Science, Multidisciplinary
Bo Fu, Zi-Ang Hu, Chang-An Li, Jian Li, Shun-Qing Shen
Summary: Chiral Majorana hinge modes are characteristic of a second-order topological superconductor in three dimensions. The study suggests the strong spin-orbital coupling, crystalline symmetries, and electron-electron interaction in Dirac materials may provide a platform to realize chiral Majorana hinge modes with no proximity effect or external fields. The findings also discuss possible relevance to superconductivity in ZrTe5.
Article
Physics, Multidisciplinary
V. Fernandez Becerra, Mircea Trif, Timo Hyart
Summary: We study the properties of semiconducting nanowires with induced superconductivity and ferromagnetism, and find that spin pumping is quantized in the topologically nontrivial phase while charge pumping is not. In long topologically nontrivial nanowires, there is a one-to-one correspondence between quantized conductance, entropy change, and spin pumping. The observation of correlated and quantized peaks in conductance, entropy change, and spin pumping would provide strong evidence of Majorana zero modes.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
M. J. Pacholski, G. Lemut, O. Ovdat, I Adagideli, C. W. J. Beenakker
Summary: In a Fu-Kane heterostructure, a spatially oscillating pair potential with a redundant vector can lead to a deconfinement transition of Majorana bound states, forming a dispersionless Landau level. The coherent superposition of electrons and holes in the Majorana Landau level can be detected through local density oscillations, and the striped pattern provides a way to measure the chirality of the Majorana fermions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Markus F. Ritter, Heinz Schmid, Marilyne Sousa, Philipp Staudinger, Daniel Z. Haxell, M. A. Mueed, Benjamin Madon, Aakash Pushp, Heike Riel, Fabrizio Nichele
Summary: The integration of high-quality semiconductor-superconductor devices into scalable and CMOS-compatible architectures remains a challenge, but a new technique has been demonstrated here using InAs nanowires grown monolithically on silicon with superconducting TiN elements. Electrical characterization at low temperatures showed proximity induced superconductivity in InAs via a transparent interface.
Article
Physics, Applied
Omri Lesser, Yuval Oreg
Summary: Majorana zero modes have attracted much interest due to their non-Abelian exchange statistics and potential applications in topological quantum computation. Breaking time-reversal symmetry is essential to form Majorana zero modes in quasi-one-dimensional topological insulators, however direct experimental detection has been challenging. This review discusses several proposals that focus on controlling the phase of the superconducting order parameter, aiming to improve Majorana formation and understand the underlying physics of topological superconducting state formation.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Vedangi Pathak, Sayak Dasgupta, Marcel Franz
Summary: In this study, we propose a new platform for realizing Majorana zero modes using a thin-film heterostructure composed of an easy-plane ferromagnet and a superconductor with spin-orbit coupling. The system can support a stable zero-energy Majorana bound state and exhibits a rich interplay between magnetism and superconductivity.
Article
Materials Science, Multidisciplinary
Xiaoming Zhang, Feng Liu
Summary: The study shows that Majorana edge states can be achieved by magnetizing topological surface states, with the axion insulator state realizing helical MES. The stability of the TSC phase is determined by comparing the square of the sum of two superconducting gaps. By predicting MnBi2Te4/Bi2Te3 film on a superconducting substrate as an experimental platform, chiral MESs can be realized within a wide energy range.
Article
Multidisciplinary Sciences
A. Ibabe, M. Gomez, G. O. Steffensen, T. Kanne, J. Nygard, A. Levy Yeyati, E. J. H. Lee
Summary: In this study, we find that measurements of the superconductor-to-normal transition resulting from Joule heating can be used as a powerful spectroscopical tool to characterize hybrid superconductor-semiconductor devices. By applying this technique to junctions in Al-InAs nanowires, we obtain detailed information of each lead independently, including differences in superconducting coherence lengths, inhomogeneous covering of the epitaxial shell, and the inverse superconducting proximity effect, which can serve as a unique fingerprint for each device with applications in data interpretation, device optimization, and disorder analysis. Our work highlights the importance of heating in hybrid devices, an effect that is often overlooked.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Philip Harder, Andreas Nielsen, Ann-Katrin Sassnau, Dennis Bonatz, Markus Perbandt, Tobias Kipp, Alf Mews
Summary: The study investigates the structural properties of CdS, CdSe, and CdTe semiconductor nanowires grown by the SLS method through a detailed experimental and simulation approach. The different samples show varying fractions of Wurtzite and Zincblende, as determined by high-resolution TEM and p-XRD analysis of selected wires and a large amount of NWs.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Mikelis Marnauza, Robin Sjokvist, Sebastian Lehmann, Kimberly A. A. Dick
Summary: Environmental transmission electron microscopy is used to study the growth of Au nanoparticle seeded GaSb nanowires in situ. It is found that the precursor V/III ratio affects the morphology, composition, and diameter of the nanowires. The observed trends can be reproduced in a conventional exsitu system, highlighting the transferability and importance of the results obtained in situ.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
R. C. Bento Ribeiro, J. H. Correa, L. S. Ricco, I. A. Shelykh, Mucio A. Continentino, A. C. Seridonio, M. Minissale, G. Le Lay, M. S. Figueira
Summary: We propose penta-silicene nanoribbons (p-SiNRs) with induced p-wave superconductivity as a platform for spin-polarized Majorana zero-modes (MZMs). The system consists of Rashba spin-orbit coupling, perpendicular magnetic field, first nearest neighbor hopping, and p-wave superconducting pairing. The energy spectrum of the system reveals the existence of MZMs localized at the ends of the p-SiNR with well-defined spin orientation. Experimental techniques can fabricate ordered p-SiNRs with a thin lead film for inducing p-wave superconductivity. This study opens up new possibilities for exploring quantum computing and spin-polarized electronic transport mechanisms.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
Thomas Kanne, Dags Olsteins, Mikelis Marnauza, Alexandros Vekris, Juan Carlos Estrada Saldana, Sara Loric, Rasmus D. Schlosser, Daniel Ross, Szabolcs Csonka, Kasper Grove-Rasmussen, Jesper Nygard
Summary: The core platform of several recent quantum device proposals relies on parallel 1D semiconductor channels connected by a superconducting strip, utilizing Andreev processes or topological effects. A strategy for synthesizing double InAs nanowires using III-V molecular beam epitaxy is presented, allowing for the deposition of a superconducting layer onto nanowires without breaking the vacuum in order to ensure pristine interfaces between the superconductor and the semiconductor nanowires. The method demonstrates the utility of high yield merged or separate parallel nanowires with full or half-shell superconductor coatings in complex quantum devices through electron transport measurements.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Seongjin Ahn, Sankar Das Sarma
Summary: We used the Boltzmann transport theory to calculate the density-dependent mobility of 2D electrons in GaAs, SiGe, and AlAs quantum wells, as well as 2D holes in GaAs quantum wells. It was found that the mobility of electrons in GaAs quantum wells is limited by low concentrations of unintended background random charged impurities. This low level of background disorder also leads to higher theoretical limits for the mobility of 2D GaAs holes and 2D AlAs electrons.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Physics, Multidisciplinary
Sankar Das Sarma
Summary: Majorana particles, which are the same as their antiparticles, show promise for quantum computing in condensed matter systems. This article discusses the search for Majorana modes in semiconductor heterostructures and the limitations imposed by disorder. Majorana zero modes are emergent phenomena in topological superconductors, and this Perspective provides an overview of their physics, recent experimental progress, and future outlook for success.
Article
Physics, Multidisciplinary
DinhDuy Vu, Sankar Das Sarma
Summary: An ergodic system subjected to an external periodic drive will be heated to infinite temperature, but this heating can be stopped during a prethermal period if the applied frequency is larger than the typical energy scale of the local Hamiltonian. This prethermal period exhibits an emergent symmetry that, if broken, leads to subharmonic oscillation of the discrete time crystal (DTC). The presence of dissipation affects the survival time of the prethermal DTC, with a bath coupling prolonging the prethermal period and interaction with the environment destabilizing spontaneous symmetry breaking, resulting in a nonmonotonic variation of the survival time.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Jiabin Yu, Ming Xie, Fengcheng Wu, Sankar Das Sarma
Summary: Signatures of nematic nodal superconductivity have been observed in magic angle twisted bilayer graphene. Researchers propose a general topological mechanism explaining how nematic pairing leads to nodal superconductivity in this material.
Article
Materials Science, Multidisciplinary
Prathyush P. Poduval, Sankar Das Sarma
Summary: We theoretically investigate the issue of doping induced insulator to metal transition in bulk semiconductors by analyzing the density-dependent mean free path and the Anderson localization transition controlled by the Ioffe-Regel-Mott (IRM) criterion. We calculate the mean free path on the highly doped metallic side considering carrier scattering by ionized dopants. The Coulomb disorder of the charged dopants is screened by the carriers themselves, leading to an integral equation for localization. By solving this equation analytically and numerically, we provide detailed results for the critical density of the doping induced metal-insulator transition.
Article
Materials Science, Multidisciplinary
Nathan L. Foulk, Sankar Das Sarma
Summary: We demonstrate the potential realization of quantum Floquet matter, particularly the discrete time crystal (DTC), using modern silicon spin qubits based in quantum dots. This is significant as silicon spin qubits have advantages in dealing with charge noise. We show the differences between prethermal phenomena and true time-crystalline spatiotemporal order, and illustrate rich regime structures in a spin chain of four qubits that are distinct from the thermal regime.
Article
Materials Science, Multidisciplinary
Seth M. Davis, Yang-Zhi Chou, Fengcheng Wu, Sankar Das Sarma
Summary: We calculate the theoretical contribution of scattering by acoustic phonons to the doping and temperature dependence of electrical resistivity in Bernal bilayer graphene (BBG) and rhombohedral trilayer graphene (RTG). The nontrivial geometric features of the band structures of these systems strongly influence the resistivity's temperature and doping dependencies. Our focus on BBG and RTG is motivated by recent experiments in these systems that have discovered exotic low-temperature superconductivity. The understanding of the influence of band geometry on transport is crucial in these systems.
Article
Materials Science, Multidisciplinary
Haining Pan, Sankar Das Sarma
Summary: Motivated by the presence of Majorana zero modes in both the Kitaev chain model and the experimental semiconductor-superconductor Majorana nanowire, this theoretical study investigates the equivalence or similarity between the two models from the perspective of their corresponding dual spin models. By using the Jordan-Wigner transformation, the duality between the Kitaev chain and the transverse-field XY spin model is established, aiming to connect the Kitaev chain and the nanowire. The application of the Jordan-Wigner transformation to the nanowire reveals that the corresponding bosonic spin model is a generalized spin cluster model with staggered couplings. By projecting out the higher energy band of the spinful nanowire system, an effective low-energy spinless system is obtained, leading to the connection between the Kitaev chain and Majorana nanowire.
Article
Materials Science, Multidisciplinary
Yi-Ting Tu, Sankar Das Sarma
Summary: We analyze an experimental work which shows the failure of the Wiedemann-Franz law in graphene at low temperatures, attributing this failure to the non-Fermi liquid nature of the Dirac fluid. Despite theoretical efforts, the observations remain unexplained. Our analysis suggests that the opening of a gap at the Dirac point induced by the substrate may explain the results. Further experiments are needed to resolve the issue and determine the role of electron and hole transport in the presence of disorder and phonons.
Article
Materials Science, Multidisciplinary
Yi-Ting Tu, DinhDuy Vu, S. Das Sarma
Summary: Coupling a one-dimensional quasiperiodic interacting system to a Markovian bath, this study investigates the avalanche instability of the many-body localized phase numerically. The results show that many-body localization (MBL) is more stable in pseudorandom quasiperiodic systems than in randomly disordered systems for a disorder strength W > 8, potentially up to arbitrarily large system sizes. Real-space RG arguments support this conclusion and a detailed comparison between quasiperiodic and random MBL from the avalanche instability perspective reveals that they belong to different universality classes.
Article
Materials Science, Multidisciplinary
Donovan Buterakos, Sankar Das Sarma
Summary: We discuss interesting phenomena in the Hubbard model related to flat-band ferromagnetism. The first is a mathematical theorem that describes the conditions for degeneracy between a flat-band ferromagnetic and a nonferromagnetic state. This theorem is generally applicable and independent of geometry, but only holds for a small number of holes in a filled band. The second phenomenon challenges intuition by showing an example where particles do not prefer to doubly occupy low-energy states before filling higher-energy states. Lastly, we present a pattern of ferromagnetism in small pentagonal and hexagonal plaquettes at specific filling factors. These examples can be observed in quantum dot arrays available in laboratories.
Article
Materials Science, Multidisciplinary
Yi-Hua Lai, Sankar Das Sarma, Jay D. Sau
Summary: Despite recent progress in experimental observations of large zero-bias conductance peaks, it is still unclear whether Majorana modes have been observed. The existing experimental works lack stability of the putative Majorana mode features, indicating the absence of a topological phase. This paper introduces a dimensionless quality factor F to quantify the robustness of the zero-bias conductance peak height and proposes specific experimentally accessible measures for analyzing the stability of the observed peaks. The results show that Majorana modes are significantly more robust compared to nontopological peaks in the low-temperature limit and suggest that the quality factor F can be used to estimate the quality of topological qubits made from Majorana modes.
Article
Materials Science, Multidisciplinary
Johannes Hofmann, Sankar Das Sarma
Summary: We develop a model for interacting two-dimensional Fermi liquids with different collisional relaxation rates for parity-odd and parity-even Fermi surface deformations. We derive expressions for both the longitudinal and transverse conductivity and discuss the collective mode spectrum in different transport regimes. Our work demonstrates the existence of deep many-body aspects of interacting Fermi liquids that have not been fully understood theoretically.
Article
Materials Science, Multidisciplinary
Seongjin Ahn, Sankar Das Sarma
Summary: We developed a minimal theory for the metal-insulator transition observed in two-dimensional moire multilayer transition metal dichalcogenides, attributing it to Coulomb disorder in the environment. Carrier scattering by random charged impurities leads to an effective 2D MIT roughly controlled by the Ioffe-Regel criterion, with necessary random charged impurity content consistent with known levels in TMDs.
Article
Materials Science, Multidisciplinary
Haining Pan, Sankar Das Sarma
Summary: This study theoretically investigates the strong correlation and symmetry breaking behaviors in two-dimensional moire transition metal dichalcogenide bilayers. The dependence of symmetry breaking on the range of electron-electron interaction and temperature is examined, with implications for experimental control and thermal suppression.
