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49 results on '"Cui, Ajuan"'

1. Interferometric Single-Shot Parity Measurement in an InAs-Al Hybrid Device

Author

Aghaee, Morteza, Ramirez, Alejandro Alcaraz, Alam, Zulfi, Ali, Rizwan, Andrzejczuk, Mariusz, Antipov, Andrey, Astafev, Mikhail, Barzegar, Amin, Bauer, Bela, Becker, Jonathan, Bhaskar, Umesh Kumar, Bocharov, Alex, Boddapati, Srini, Bohn, David, Bommer, Jouri, Bourdet, Leo, Bousquet, Arnaud, Boutin, Samuel, Casparis, Lucas, Chapman, Benjamin James, Chatoor, Sohail, Christensen, Anna Wulff, Chua, Cassandra, Codd, Patrick, Cole, William, Cooper, Paul, Corsetti, Fabiano, Cui, Ajuan, Dalpasso, Paolo, Dehollain, Juan Pablo, de Lange, Gijs, de Moor, Michiel, Ekefjärd, Andreas, Dandachi, Tareq El, Saldaña, Juan Carlos Estrada, Fallahi, Saeed, Galletti, Luca, Gardner, Geoff, Govender, Deshan, Griggio, Flavio, Grigoryan, Ruben, Grijalva, Sebastian, Gronin, Sergei, Gukelberger, Jan, Hamdast, Marzie, Hamze, Firas, Hansen, Esben Bork, Heedt, Sebastian, Heidarnia, Zahra, Zamorano, Jesús Herranz, Ho, Samantha, Holgaard, Laurens, Hornibrook, John, Indrapiromkul, Jinnapat, Ingerslev, Henrik, Ivancevic, Lovro, Jensen, Thomas, Jhoja, Jaspreet, Jones, Jeffrey, Kalashnikov, Konstantin V., Kallaher, Ray, Kalra, Rachpon, Karimi, Farhad, Karzig, Torsten, King, Evelyn, Kloster, Maren Elisabeth, Knapp, Christina, Kocon, Dariusz, Koski, Jonne, Kostamo, Pasi, Kumar, Mahesh, Laeven, Tom, Larsen, Thorvald, Lee, Jason, Lee, Kyunghoon, Leum, Grant, Li, Kongyi, Lindemann, Tyler, Looij, Matthew, Love, Julie, Lucas, Marijn, Lutchyn, Roman, Madsen, Morten Hannibal, Madulid, Nash, Malmros, Albert, Manfra, Michael, Mantri, Devashish, Markussen, Signe Brynold, Martinez, Esteban, Mattila, Marco, McNeil, Robert, Mei, Antonio B., Mishmash, Ryan V., Mohandas, Gopakumar, Mollgaard, Christian, Morgan, Trevor, Moussa, George, Nayak, Chetan, Nielsen, Jens Hedegaard, Nielsen, Jens Munk, Nielsen, William Hvidtfelt Padkær, Nijholt, Bas, Nystrom, Mike, O'Farrell, Eoin, Ohki, Thomas, Otani, Keita, Wütz, Brian Paquelet, Pauka, Sebastian, Petersson, Karl, Petit, Luca, Pikulin, Dima, Prawiroatmodjo, Guen, Preiss, Frank, Morejon, Eduardo Puchol, Rajpalke, Mohana, Ranta, Craig, Rasmussen, Katrine, Razmadze, David, Reentila, Outi, Reilly, David J., Ren, Yuan, Reneris, Ken, Rouse, Richard, Sadovskyy, Ivan, Sainiemi, Lauri, Sanlorenzo, Irene, Schmidgall, Emma, Sfiligoj, Cristina, Shah, Mustafeez Bashir, Simoes, Kevin, Singh, Shilpi, Sinha, Sarat, Soerensen, Thomas, Sohr, Patrick, Stankevic, Tomas, Stek, Lieuwe, Stuppard, Eric, Suominen, Henri, Suter, Judith, Teicher, Sam, Thiyagarajah, Nivetha, Tholapi, Raj, Thomas, Mason, Toomey, Emily, Tracy, Josh, Turley, Michelle, Upadhyay, Shivendra, Urban, Ivan, Van Hoogdalem, Kevin, Van Woerkom, David J., Viazmitinov, Dmitrii V., Vogel, Dominik, Watson, John, Webster, Alex, Weston, Joseph, Winkler, Georg W., Xu, Di, Yang, Chung Kai, Yucelen, Emrah, Zeisel, Roland, Zheng, Guoji, and Zilke, Justin

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The fusion of non-Abelian anyons or topological defects is a fundamental operation in measurement-only topological quantum computation. In topological superconductors, this operation amounts to a determination of the shared fermion parity of Majorana zero modes. As a step towards this, we implement a single-shot interferometric measurement of fermion parity in indium arsenide-aluminum heterostructures with a gate-defined nanowire. The interferometer is formed by tunnel-coupling the proximitized nanowire to quantum dots. The nanowire causes a state-dependent shift of these quantum dots' quantum capacitance of up to 1 fF. Our quantum capacitance measurements show flux h/2e-periodic bimodality with a signal-to-noise ratio of 1 in 3.7 $\mu$s at optimal flux values. From the time traces of the quantum capacitance measurements, we extract a dwell time in the two associated states that is longer than 1 ms at in-plane magnetic fields of approximately 2 T. These results are consistent with a measurement of the fermion parity encoded in a pair of Majorana zero modes that are separated by approximately 3 $\mu$m and subjected to a low rate of poisoning by non-equilibrium quasiparticles. The large capacitance shift and long poisoning time enable a parity measurement error probability of 1%., Comment: Added data on a second measurement of device A and a measurement of device B, expanded discussion of a trivial scenario. Refs added, author list updated

Published
2024

2. InAs-Al Hybrid Devices Passing the Topological Gap Protocol

Author

Aghaee, Morteza, Akkala, Arun, Alam, Zulfi, Ali, Rizwan, Ramirez, Alejandro Alcaraz, Andrzejczuk, Mariusz, Antipov, Andrey E, Aseev, Pavel, Astafev, Mikhail, Bauer, Bela, Becker, Jonathan, Boddapati, Srini, Boekhout, Frenk, Bommer, Jouri, Hansen, Esben Bork, Bosma, Tom, Bourdet, Leo, Boutin, Samuel, Caroff, Philippe, Casparis, Lucas, Cassidy, Maja, Christensen, Anna Wulf, Clay, Noah, Cole, William S, Corsetti, Fabiano, Cui, Ajuan, Dalampiras, Paschalis, Dokania, Anand, de Lange, Gijs, de Moor, Michiel, Saldaña, Juan Carlos Estrada, Fallahi, Saeed, Fathabad, Zahra Heidarnia, Gamble, John, Gardner, Geoff, Govender, Deshan, Griggio, Flavio, Grigoryan, Ruben, Gronin, Sergei, Gukelberger, Jan, Heedt, Sebastian, Zamorano, Jesús Herranz, Ho, Samantha, Holgaard, Ulrik Laurens, Nielsen, William Hvidtfelt Padkær, Ingerslev, Henrik, Krogstrup, Peter Jeppesen, Johansson, Linda, Jones, Jeffrey, Kallaher, Ray, Karimi, Farhad, Karzig, Torsten, King, Evelyn, Kloster, Maren Elisabeth, Knapp, Christina, Kocon, Dariusz, Koski, Jonne, Kostamo, Pasi, Kumar, Mahesh, Laeven, Tom, Larsen, Thorvald, Li, Kongyi, Lindemann, Tyler, Love, Julie, Lutchyn, Roman, Manfra, Michael, Memisevic, Elvedin, Nayak, Chetan, Nijholt, Bas, Madsen, Morten Hannibal, Markussen, Signe, Martinez, Esteban, McNeil, Robert, Mullally, Andrew, Nielsen, Jens, Nurmohamed, Anne, O'Farrell, Eoin, Otani, Keita, Pauka, Sebastian, Petersson, Karl, Petit, Luca, Pikulin, Dima, Preiss, Frank, Perez, Marina Quintero, Rasmussen, Katrine, Rajpalke, Mohana, Razmadze, Davydas, Reentila, Outi, Reilly, David, Rouse, Richard, Sadovskyy, Ivan, Sainiemi, Lauri, Schreppler, Sydney, Sidorkin, Vadim, Singh, Amrita, Singh, Shilpi, Sinha, Sarat, Sohr, Patrick, Stankevič, Tomaš, Stek, Lieuwe, Suominen, Henri, Suter, Judith, Svidenko, Vicky, Teicher, Sam, Temuerhan, Mine, Thiyagarajah, Nivetha, Tholapi, Raj, Thomas, Mason, Toomey, Emily, Upadhyay, Shivendra, Urban, Ivan, Vaitiekėnas, Saulius, Van Hoogdalem, Kevin, Viazmitinov, Dmitrii V., Waddy, Steven, Van Woerkom, David, Vogel, Dominik, Watson, John, Weston, Joseph, Winkler, Georg W., Yang, Chung Kai, Yau, Sean, Yi, Daniel, Yucelen, Emrah, Webster, Alex, Zeisel, Roland, and Zhao, Ruichen

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We present measurements and simulations of semiconductor-superconductor heterostructure devices that are consistent with the observation of topological superconductivity and Majorana zero modes. The devices are fabricated from high-mobility two-dimensional electron gases in which quasi-one-dimensional wires are defined by electrostatic gates. These devices enable measurements of local and non-local transport properties and have been optimized via extensive simulations to ensure robustness against non-uniformity and disorder. Our main result is that several devices, fabricated according to the design's engineering specifications, have passed the topological gap protocol defined in Pikulin et al. [arXiv:2103.12217]. This protocol is a stringent test composed of a sequence of three-terminal local and non-local transport measurements performed while varying the magnetic field, semiconductor electron density, and junction transparencies. Passing the protocol indicates a high probability of detection of a topological phase hosting Majorana zero modes as determined by large-scale disorder simulations. Our experimental results are consistent with a quantum phase transition into a topological superconducting phase that extends over several hundred millitesla in magnetic field and several millivolts in gate voltage, corresponding to approximately one hundred micro-electron-volts in Zeeman energy and chemical potential in the semiconducting wire. These regions feature a closing and re-opening of the bulk gap, with simultaneous zero-bias conductance peaks at both ends of the devices that withstand changes in the junction transparencies. The extracted maximum topological gaps in our devices are 20-60 $\mu$eV. This demonstration is a prerequisite for experiments involving fusion and braiding of Majorana zero modes., Comment: Final version

Published
2022
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3. Transparent Gatable Superconducting Shadow Junctions

Author

Khan, Sabbir A., Lampadaris, Charalampos, Cui, Ajuan, Stampfer, Lukas, Liu, Yu, Pauka, S. J., Cachaza, Martin E., Fiordaliso, Elisabetta M., Kang, Jung-Hyun, Korneychuk, Svetlana, Mutas, Timo, Sestoft, Joachim E., Krizek, Filip, Tanta, Rawa, Cassidy, M. C., Jespersen, Thomas S., and Krogstrup, Peter

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Superconductivity, Physics - Applied Physics, Quantum Physics
Abstract

Gate tunable junctions are key elements in quantum devices based on hybrid semiconductor-superconductor materials. They serve multiple purposes ranging from tunnel spectroscopy probes to voltage-controlled qubit operations in gatemon and topological qubits. Common to all is that junction transparency plays a critical role. In this study, we grow single crystalline InAs, InSb and $\mathrm{InAs_{1-x}Sb_x}$ nanowires with epitaxial superconductors and in-situ shadowed junctions in a single-step molecular beam epitaxy process. We investigate correlations between fabrication parameters, junction morphologies, and electronic transport properties of the junctions and show that the examined in-situ shadowed junctions are of significantly higher quality than the etched junctions. By varying the edge sharpness of the shadow junctions we show that the sharpest edges yield the highest junction transparency for all three examined semiconductors. Further, critical supercurrent measurements reveal an extraordinarily high $I_\mathrm{C} R_\mathrm{N}$, close to the KO$-$2 limit. This study demonstrates a promising engineering path towards reliable gate-tunable superconducting qubits., Comment: 10 pages, 5 figures, 48 references

Published
2020

4. A Training effect on electrical properties in nanoscale BiFeO$_3$

Author

Goswami, Sudipta, Bhattacharya, Dipten, Li, Wuxia, Cui, Ajuan, Jiang, QianQing, and Gu, Chang-zhi

Subjects
Condensed Matter - Materials Science
Abstract

We report our observation of the training effect on dc electrical properties in a nanochain of BiFeO$_3$ as a result of large scale migration of defects under combined influence of electric field and Joule heating. We show that an optimum number of cycles of electric field within the range zero to $\sim$1.0 MV/cm across a temperature range 80-300 K helps in reaching the stable state via a glass-transition-like process in the defect structure. Further treatment does not give rise to any substantial modification. We conclude that such a training effect is ubiquitous in pristine nanowires or chains of oxides and needs to be addressed for applications in nanoelectronic devices., Comment: 11 pages with 5 figures; published in Nanotechnology

Published
2013
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14. Highly Transparent Gatable Superconducting Shadow Junctions

Author

Khan, Sabbir A., Lampadaris, Charalampos, Cui, Ajuan, Stampfer, Lukas, Liu, Yu, Pauka, Sebastian J., Cachaza, Martin E., Fiordaliso, Elisabetta M., Kang, Jung-Hyun, Korneychuk, Svetlana, Mutas, Timo, Sestoft, Joachim E., Krizek, Filip, Tanta, Rawa, Cassidy, Maja C., Jespersen, Thomas S., Krogstrup, Peter, Khan, Sabbir A., Lampadaris, Charalampos, Cui, Ajuan, Stampfer, Lukas, Liu, Yu, Pauka, Sebastian J., Cachaza, Martin E., Fiordaliso, Elisabetta M., Kang, Jung-Hyun, Korneychuk, Svetlana, Mutas, Timo, Sestoft, Joachim E., Krizek, Filip, Tanta, Rawa, Cassidy, Maja C., Jespersen, Thomas S., and Krogstrup, Peter

Abstract

Gate-tunable junctions are key elements in quantum devices based on hybrid semiconductor-superconductor materials. They serve multiple purposes ranging from tunnel spectroscopy probes to voltage-controlled qubit operations in gatemon and topological qubits. Common to all is that junction transparency plays a critical role. In this study, we grow single-crystalline InAs, InSb, and InAs1-xSbx semiconductor nanowires with epitaxial Al, Sn, and Pb superconductors and in situ shadowed junctions in a single-step molecular beam epitaxy process. We investigate correlations between fabrication parameters, junction morphologies, and electronic transport properties of the junctions and show that the examined in situ shadowed junctions are of significantly higher quality than the etched junctions. By varying the edge sharpness of the shadow junctions, we show that the sharpest edges yield the highest junction transparency for all three examined semiconductors. Further, critical supercurrent measurements reveal an extraordinarily high ICRN, close to the KO-2 limit. This study demonstrates a promising engineering path toward reliable gate-tunable superconducting qubits.

Published
2020

15. Highly Transparent Gatable Superconducting Shadow Junctions

Author

Khan, Sabbir A., primary, Lampadaris, Charalampos, additional, Cui, Ajuan, additional, Stampfer, Lukas, additional, Liu, Yu, additional, Pauka, Sebastian J., additional, Cachaza, Martin E., additional, Fiordaliso, Elisabetta M., additional, Kang, Jung-Hyun, additional, Korneychuk, Svetlana, additional, Mutas, Timo, additional, Sestoft, Joachim E., additional, Krizek, Filip, additional, Tanta, Rawa, additional, Cassidy, Maja C., additional, Jespersen, Thomas S., additional, and Krogstrup, Peter, additional

Published
2020
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23. Cui, Ajuan

Author

Cui, Ajuan and Cui, Ajuan

Published
2016

25. Spatially oriented plasmonic ‘nanograter’ structures

Author

Liu, Zhe, primary, Cui, Ajuan, additional, Gong, Zhijie, additional, Li, Hongqiang, additional, Xia, Xiaoxiang, additional, Shen, Tiehan H., additional, Li, Junjie, additional, Yang, Haifang, additional, Li, Wuxia, additional, and Gu, Changzhi, additional

Published
2016
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44. Ion-beam-induced bending of freestanding amorphous nanowires: The importance of the substrate material and charging.

Author

Cui, Ajuan, Fenton, J. C., Li, Wuxia, Shen, Tiehan H., Liu, Zhe, Luo, Qiang, and Gu, Changzhi

Subjects
*ION beams, *AMORPHOUS substances, *NANOWIRES, *IRRADIATION, *BENDING (Metalwork), *ELECTROSTATIC interaction, *NANOSTRUCTURES
Abstract

Ion-beam irradiation offers great flexibility and controllability in the construction of freestanding nanostructures with multiple advanced functionalities. Here, we present and discuss the bending of free-standing nanowires, against, towards, and ultimately parallel to a flux of directional ion irradiation. Bending components both along and perpendicular to the incident ion beam were observed, and the bending behavior was found to depend both on the ion beam scanning strategy and on the conductivity of the supporting substrate. This behavior is explained by an ion-irradiation-related electrostatic interaction. Our findings suggest the prospect of exploiting this technique to engineer 3D nanostructures for advanced applications. [ABSTRACT FROM AUTHOR]

Published
2013
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45. Felling of individual freestanding nanoobjects using focused-ion-beam milling for investigations of structural and transport properties.

Author

Wuxia Li, Fenton, J. C., Cui, Ajuan, Huan Wang, Yiqian Wang, Changzhi Gu, McComb, D. W., and Warburton, P. A.

Subjects
FOCUSED ion beams, STRUCTURAL analysis (Engineering), TUNGSTEN, TRANSPORT theory, NANOWIRES, PHYSICS experiments
Abstract

We report that, to enable studies of their compositional, structural and electrical properties, freestanding individual nanoobjects can be selectively felled in a controllable way by the technique of low-current focused-ion-beam (FIB) milling with the ion beam at a chosen angle of incidence to the nanoobject. To demonstrate the suitability of the technique, we report results for zigzag/straight tungsten nanowires grown vertically on support substrates and then felled for characterization. We also describe a systematic investigation of the effect of the experimental geometry and parameters on the felling process and on the induced wire-bending phenomenon. The method of felling freestanding nanoobjects using FIB is an advantageous new technique enabling investigations of the properties of selected individual nanoobjects. [ABSTRACT FROM AUTHOR]

Published
2012
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48. A General Method for Growing Two-Dimensional Crystals of Organic Semiconductors by "Solution Epitaxy".

Author

Xu C, He P, Liu J, Cui A, Dong H, Zhen Y, Chen W, and Hu W

Abstract

Two-dimensional (2D) crystals of organic semiconductors (2DCOS) have attracted attention for large-area and low-cost flexible optoelectronics. However, growing large 2DCOS in controllable ways and transferring them onto technologically important substrates, remain key challenges. Herein we report a facile, general, and effective method to grow 2DCOS up to centimeter size which can be transferred to any substrate efficiently. The method named "solution epitaxy" involves two steps. The first is to self-assemble micrometer-sized 2DCOS on water surface. The second is epitaxial growth of them into millimeter or centimeter sized 2DCOS with thickness of several molecular layers. The general applicability of this method for the growth of 2DCOS is demonstrated by nine organic semiconductors with different molecular structures. Organic field-effect transistors (OFETs) based on the 2DCOS demonstrated high performance, confirming the high quality of the 2DCOS., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2016
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49. Metal-organic frameworks reactivate deceased diatoms to be efficient CO(2) absorbents.

Author

Liu D, Gu J, Liu Q, Tan Y, Li Z, Zhang W, Su Y, Li W, Cui A, Gu C, and Zhang D

Subjects
Absorption, Physicochemical, Diatoms ultrastructure, Imidazoles chemistry, Kinetics, Magnetic Resonance Spectroscopy, Microscopy, Electron, Scanning, Microscopy, Electron, Transmission, Models, Biological, Pressure, Silicon Dioxide chemistry, Spectrum Analysis, Raman, Water chemistry, Zeolites chemistry, Carbon Dioxide chemistry, Diatomaceous Earth chemistry, Diatoms chemistry, Metals chemistry
Abstract

Diatomite combined with certain metal-organic frameworks (MOFs) is shown to be an effective CO2 absorbent, although diatomite alone is regarded as inert with respect to CO2 absorption. This finding opens the prospect of reactivating millions of tons of diatomite for CO2 absorption. It also shows for the first time that diatom frustules can act as CO2 buffers, an important link in a successive biological CO2 concentration mechanism chain that impacts on global warming., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2014
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