Article
Chemistry, Multidisciplinary
Sander. G. G. Schellingerhout, Roberto Bergamaschini, Marcel. A. A. Verheijen, Francesco Montalenti, Leo Miglio, Erik P. A. M. Bakkers
Summary: Selective area growth of Pb1-xSnxTe islands and nanowires is demonstrated, and their in-depth growth dynamics and faceting are analyzed. The material is confirmed to be single-crystalline and defect-free, with homogeneous Pb/Sn ratio in the nanowires. {110} directions are identified as the optimal candidate for the growth of high-quality and straight Pb1-xSnxTe nanowires, enabling the design of complex networks.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Peng Li, Jinjun Ding, Steven S-L Zhang, James Kally, Timothy Pillsbury, Olle G. Heinonen, Gaurab Rimal, Chong Bi, August DeMann, Stuart B. Field, Weigang Wang, Jinke Tang, Jidong Samuel Jiang, Axel Hoffmann, Nitin Samarth, Mingzhong Wu
Summary: This study reports a genuine topological Hall effect in a TI/MI structure, where the contribution of skyrmions to the Hall effect outweighs the coexistence of magnetic phases.
Article
Physics, Multidisciplinary
Yafei Ren, Cong Xiao, Daniyar Saparov, Qian Niu
Summary: The study investigates the adiabatic evolution of electronic states induced by the lattice vibration of a chiral phonon, obtaining electronic orbital magnetization in the form of a topological second Chern form. The traditional theory needs refinement by introducing a k-resolved Born effective charge and accounting for the phonon-modified electronic energy and momentum-space Berry curvature contribution. The second Chern form may diverge when a Yang's monopole is near the parameter space of interest, as demonstrated in a gapped graphene model at the Brillouin zone corner.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Qinghua Guo, Tianshu Jiang, Ruo-Yang Zhang, Lei Zhang, Zhao-Qing Zhang, Biao Yang, Shuang Zhang, C. T. Chan
Summary: Experimental observation of non-Abelian topological charges and edge states in a PT-symmetric transmission line network, along with the discovery of a non-Abelian quotient relation for the bulk-edge correspondence. This new topological property opens up possibilities for intriguing observable phenomena in the field of material science.
Article
Chemistry, Multidisciplinary
Dennis Heffels, Declan Burke, Malcolm R. R. Connolly, Peter Schueffelgen, Detlev Gruetzmacher, Kristof Moors
Summary: In this work, we present a detailed modeling approach for a topological insulator nanoribbon in contact with a superconductor, inducing superconductivity. Our simulation results indicate that a top-proximitized TI nanoribbon is ideal for realizing fully gapped topological superconductivity, especially when the Fermi level is near the Dirac point, resulting in robust quantized zero-bias conductance peak.
Article
Physics, Multidisciplinary
Ruochen Ma, Chong Wang
Summary: In this study, we demonstrate that symmetry-protected topological (SPT) phases can also be applied to average symmetries, where local quenched disorders break the symmetries but restore them upon disorder averaging. We classify and characterize a large class of average SPT phases using a decorated domain wall approach, and show that the boundary states of such phases will almost certainly be long-range entangled. We also develop a theory for generalized average SPT phases based on density matrices and quantum channels, indicating that topological quantum phenomena associated with average symmetries can be as rich as those with exact symmetries.
Article
Physics, Multidisciplinary
Y. X. Zhao, Cong Chen, Xian-Lei Sheng, Shengyuan A. Yang
Summary: The study reveals the possibility of switching the two fundamental classes via Z(2) projective representations, allowing for unique topological phases to be achieved in different classes. For PT symmetry, the occurrence of this switching mechanism is demonstrated when P inverses the gauge transformation required to recover the original Z(2) gauge connections under P.
PHYSICAL REVIEW LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Jiawei Shen, Yi He, Cheng Gao, Xiangming Tao, Bo Yang, Miao Wang, Gaoxiang Ye
Summary: In this study, MoS2 sheets with an average size of micrometers were successfully synthesized on an ionic liquid surface using a modified low-pressure chemical vapor deposition method without the assistance of catalysts. The MoS2 sheets grown on the liquid substrate exhibited a complete molecular crystal structure, as confirmed by TEM, Raman spectroscopy, and PL spectroscopy measurements. The growth mechanism of these MoS2 sheets was presented based on the experimental results. This work provides a new and simple method for preparing molecular crystals on liquid substrates and contributes to further research in this field.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Jing Zhang, Yangyang Lv, Xiaolong Feng, Aiji Liang, Wei Xia, Sung-Kwan Mo, Cheng Chen, Jiamin Xue, Shengyuan A. Yang, Lexian Yang, Yanfeng Guo, Yanbin Chen, Yulin Chen, Zhongkai Liu
Summary: Emergent physics that does not exist in three dimensions is observed in condensed matter systems in low dimensions. The characteristic one-dimensional Dirac fermion electronic structure is systematically investigated, and the system NbSixTe2 is proven to be a topological semimetal. With the adjustment of composition, the Dirac fermion undergoes a dimension-crossover from one-dimensional to two-dimensional.
NPJ QUANTUM MATERIALS
(2022)
Article
Physics, Multidisciplinary
Ari M. Turner, Erez Berg, Ady Stern
Summary: In this study, the stability of fragile topological bands protected by space-time inversion symmetry under strong electron-electron interactions is investigated. It is found that when these fragile bands are half filled, interactions can open a gap in the many-body spectrum without breaking any symmetry or mixing degrees of freedom from remote bands. The resulting ground state is not topologically ordered. The formation of fermionic bound states known as trions is crucial for this result, which may be relevant to recent experiments in magic angle twisted bilayer graphene at charge neutrality.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Nirjhar Bhattacharjee, Krishnamurthy Mahalingam, Adrian Fedorko, Valeria Lauter, Matthew Matzelle, Bahadur Singh, Alexander Grutter, Alexandria Will-Cole, Michael Page, Michael McConney, Robert Markiewicz, Arun Bansil, Don Heiman, Nian Xiang Sun
Summary: Breaking time-reversal symmetry by introducing magnetic order creates a novel topological antiferromagnetic phase. The results of this study provide a pathway towards industrial heterostructures for topological quantum devices.
ADVANCED MATERIALS
(2022)
Article
Multidisciplinary Sciences
P. J. Heikkinen, A. Casey, L. V. Levitin, X. Rojas, A. Vorontsov, P. Sharma, N. Zhelev, J. M. Parpia, J. Saunders
Summary: The research on surface Andreev bound states in superfluid He-3 demonstrates that they are fragile with respect to the details of surface scattering, unlike the robust surface/edge states in topological insulators and quantum Hall systems. The unexpectedly large suppression of T-c due to surface magnetic scattering leads to an increased density of low energy bound states.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Wei Chen
Summary: We propose a universal topological marker that can map the topological order to lattice sites for topological insulators and superconductors with Dirac models in any dimension and symmetry class. By introducing a topological operator derived from a momentum-space universal topological invariant, we construct the topological marker by alternating projectors, position operators, and Dirac matrices. The off-diagonal elements of the topological operator yield a non-local topological marker, representing a Wannier state correlation function, which decays with a diverging correlation length at topological phase transitions. Various prototype examples are employed to demonstrate the universality of our formalism.
Article
Multidisciplinary Sciences
Haiming Deng, Lukas Zhao, Kyungwha Park, Jiaqiang Yan, Kamil Sobczak, Ayesha Lakra, Entela Buzi, Lia Krusin-Elbaum
Summary: This study reports reversible binding of H+ ions to chalcogens in topological insulators and magnets, allowing for the tuning of the Fermi level without altering carrier mobility or the bandstructure. The hydrogen-tuned topological nanostructures are stable at room temperature, opening up a range of possibilities for harnessing emergent topological states.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Yang Long, Baile Zhang
Summary: We develop an unsupervised classification method to categorize topological gapped systems with symmetries and construct the topological periodic table without prior knowledge of topological invariants. This data-driven strategy can consider spatial symmetries and further classify phases previously categorized as trivial. Our research introduces machine learning into topological phase classification and facilitates intelligent exploration of new phases of topological matter.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Xiaobo Li, Mengmeng Meng, Shaoyun Huang, Congwei Tan, Congcong Zhang, Hailin Peng, H. Q. Xu
Summary: We experimentally studied the quantum transport in a topological insulator Bi2Te3 nanoplate and found that the carrier density in the nanoplate decreases while the mobility increases with decreasing top-gate voltage. Low-field magnetotransport measurements showed weak anti-localization characteristics. By considering the surface-bulk coherent electron scattering, we extracted important parameters such as dephasing times, diffusion coefficients, and surface-bulk scattering times, which helped us understand the quantum transport measurements at low temperatures.
Article
Nanoscience & Nanotechnology
Li Zhang, Yuanjie Chen, Dong Pan, Shaoyun Huang, Jianhua Zhao, H. Q. Xu
Summary: InSb nanosheet/hBN/graphite trilayers were fabricated and characterized, and single- and double-gate devices made from the trilayers were realized. The measurements showed high electron field-effect mobility and well-defined Shubnikov-de Haas oscillations in the InSb nanosheet.
Article
Physics, Multidisciplinary
Yosuke Sato, Kento Ueda, Yuusuke Takeshige, Hiroshi Kamata, Kan Li, Lars Samuelson, H. Q. Xu, Sadashige Matsuo, Seigo Tarucha
Summary: The Josephson junction of a strong spin-orbit material under a magnetic field can exhibit supercurrent enhancement, which has been attributed to topological transitions. However, this work suggests a non-topological origin, proposing that the trapping of quasiparticles by vortices explains the observed phenomena. The observed hysteresis of the switching current provides support for this explanation. This experiment highlights the importance of quasiparticles in superconducting devices with a magnetic field, offering important insights for the design of qubits using superconductors.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Applied
Xiaobo Li, Haitian Su, H. Q. Xu
Summary: A thin, narrow-bandgap semiconductor Bi2O2Te nanosheet was obtained and studied, revealing its quasi-2D and strong disordered electron transport with strong spin-orbit interaction and classical origin.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Multidisciplinary
Li Zhang, Dong Pan, Yuanjie Chen, Jianhua Zhao, Hongqi Xu
Summary: The electron transport properties in a gated Hall-bar device made from an epitaxially grown, free-standing InSb nanosheet on a hexagonal boron nitride (hBN) dielectric/graphite gate structure have been studied. It was found that the carriers in the InSb nanosheet are electrons and their density can be efficiently controlled by the graphite gate. The mobility of the electrons in the nanosheet has been extracted, and high-field magnetotransport measurements reveal well-defined Shubnikov-de Haas (SdH) oscillations. The study provides valuable insights for the development of advanced quantum devices.
Article
Physics, Multidisciplinary
Minchul Lee, Rosa Lopez, H. Q. Xu, Gloria Platero
Summary: The competition between Kondo correlation and superconductivity in quantum-dot Josephson junctions can drive a quantum phase transition between 0 and p junctions. By investigating the magnetic-field-driven phase transition in the Kondo regime, researchers found a unique feature in low-field magnetotransport that can be used to distinguish intermediate phases. The magnetic-field-driven p'-p transition was found to enhance the supercurrent, which is strongly related to the Kondo effect.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Applied
Zhencun Pan, Dong Pan, Yifeng Zhou, Jianhua Zhao, H. Q. Xu, Shaoyun Huang
Summary: Dual-gate structures were fabricated on a high-quality InAs/GaSb core/shell nanowire, enabling control of the band structure and Fermi level in the crossed bandgap heterostructure. Ambipolar transport characteristics derived separately from n-type InAs and p-type GaSb were demonstrated. An energy gap, which could be closed by adjusting the electric fields of dual gates, appeared and showed a weak and non-vanishing energy gap after closure. The reopened energy gap was suppressed in an in-plane magnetic field perpendicular to the axis of the nanowire, indicating an electron-hole interaction induced hybridization gap.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Ding-Ming Huang, Xu Wu, Kai Chang, Hao Hu, Ye-Liang Wa, H. Q. Xu, Jian-Jun Zhang
Summary: Van der Waals (vdW) layered materials have rich novel physical properties, which strongly depend on their structures. The strain effects in a kind of vdW layered material of spiral antimonene grown on a germanium (Ge) substrate are studied. Spontaneous inter-layer twist and in-plane anisotropic strain are observed in scanning tunneling microscope (STM) measurements. The strain in the spiral antimonene can be significantly modified by STM tip interaction, leading to a variation in the surface electronic density of states (DOS) and a large modification in the work function, which may have potential applications in building up novel piezoelectric devices.
Article
Quantum Science & Technology
Weijie Li, Zhihai Liu, Jingwei Mu, Yi Luo, Dong Pan, Jianhua Zhao, H. Q. Xu
Summary: A serial triple quantum dot (TQD) integrated with a quantum dot (QD) charge sensor was successfully realized using a fine finger-gate technique applied to an InAs nanowire. The complex charge states and intriguing properties of the TQD were studied in the few-electron regime through direct transport measurements and charge-sensor detection measurements. The TQD's charge stability diagrams were measured by the charge sensor and were well reproduced by simultaneous direct transport measurements and simulations based on an effective capacitance network model. In addition, the TQD was demonstrated and discussed as a quantum cellular automaton.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Chemistry, Multidisciplinary
Shili Yan, Haitian Su, Dong Pan, Weijie Li, Zhaozheng Lyu, Mo Chen, Xingjun Wu, Li Lu, Jianhua Zhao, Ji-Yin Wang, Hongqi Xu
Summary: We conducted an experimental study on proximity-induced superconductivity in planar Josephson junction devices using free-standing InAs nanosheets. The nanosheets were grown by molecular beam epitaxy, and the devices were fabricated by directly contacting the nanosheets with Al electrodes. Low-temperature measurements showed gate-tunable supercurrent, multiple Andreev reflections, and a good quality superconductor-semiconductor interface. The superconducting characteristics of the Josephson junctions were analyzed based on the BCS theory at different magnetic fields and temperatures. The ac Josephson effect measurements under microwave radiation revealed the observation of integer Shapiro steps. This work demonstrates the potential of InAs nanosheet-based hybrid devices for exploring the forefront of physics, such as two-dimensional topological superconductivity.
Article
Chemistry, Multidisciplinary
Sandra Benter, Yi Liu, Renan Da Paixao Maciel, Chin Shen Ong, Lassi Linnala, Dong Pan, Austin Irish, Yen-Po Liu, Jianhua Zhao, Hongqi Xu, Olle Eriksson, Rainer Timm, Anders Mikkelsen
Summary: This study presents new opportunities for controlling the chemical bonding between compound semiconductors and metals in nanostructures by temperature manipulation. The adsorption and incorporation of Bi on 2D InAs nanosheets were found to be temperature-dependent, and different bond configurations were observed for different crystal structures. The rate of Bi adsorption also varied significantly between InAs surfaces compared to standard Si substrates.
Article
Chemistry, Multidisciplinary
Weijie Li, Jingwei Mu, Zhi-Hai Liu, Shaoyun Huang, Dong Pan, Yuanjie Chen, Ji-Yin Wang, Jianhua Zhao, H. Q. Xu
Summary: This study presents a coupled quantum dot system consisting of two single quantum dots made in adjacent InAs nanowires, where one quantum dot acts as a charge sensor to detect charge state transitions in the other quantum dot. The researchers investigated the impact of tunneling barrier asymmetry on the detection visibility of charge state transitions in the target quantum dot.
