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Nguyen MH, Ribeill GJ, Gustafsson MV, Shi S, Aradhya SV, Wagner AP, Ranzani LM, Zhu L, Baghdadi R, Butters B, Toomey E, Colangelo M, Truitt PA, Jafari-Salim A, McAllister D, Yohannes D, Cheng SR, Lazarus R, Mukhanov O, Berggren KK, Buhrman RA, Rowlands GE, Ohki TA. Cryogenic Memory Architecture Integrating Spin Hall Effect based Magnetic Memory and Superconductive Cryotron Devices. Sci Rep 2020; 10:248. [PMID: 31937815 PMCID: PMC6959315 DOI: 10.1038/s41598-019-57137-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 11/08/2019] [Indexed: 11/09/2022] Open
Abstract
One of the most challenging obstacles to realizing exascale computing is minimizing the energy consumption of L2 cache, main memory, and interconnects to that memory. For promising cryogenic computing schemes utilizing Josephson junction superconducting logic, this obstacle is exacerbated by the cryogenic system requirements that expose the technology's lack of high-density, high-speed and power-efficient memory. Here we demonstrate an array of cryogenic memory cells consisting of a non-volatile three-terminal magnetic tunnel junction element driven by the spin Hall effect, combined with a superconducting heater-cryotron bit-select element. The write energy of these memory elements is roughly 8 pJ with a bit-select element, designed to achieve a minimum overhead power consumption of about 30%. Individual magnetic memory cells measured at 4 K show reliable switching with write error rates below 10-6, and a 4 × 4 array can be fully addressed with bit select error rates of 10-6. This demonstration is a first step towards a full cryogenic memory architecture targeting energy and performance specifications appropriate for applications in superconducting high performance and quantum computing control systems, which require significant memory resources operating at 4 K.
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Affiliation(s)
| | | | | | | | - Sriharsha V Aradhya
- Cornell University, Ithaca, NY, 14850, USA
- Western Digital Corp., Fremont, CA, 94539, USA
| | | | | | - Lijun Zhu
- Cornell University, Ithaca, NY, 14850, USA
| | - Reza Baghdadi
- Massachussetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Brenden Butters
- Massachussetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Emily Toomey
- Massachussetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Marco Colangelo
- Massachussetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Patrick A Truitt
- HYPRES, Inc., Elmsford, NY, 10523, USA
- SeeQC Inc., Elmsford, NY, 10523, USA
| | - Amir Jafari-Salim
- HYPRES, Inc., Elmsford, NY, 10523, USA
- SeeQC Inc., Elmsford, NY, 10523, USA
| | - David McAllister
- HYPRES, Inc., Elmsford, NY, 10523, USA
- Bluemont Technology, Luray, VA, 22835, USA
| | - Daniel Yohannes
- HYPRES, Inc., Elmsford, NY, 10523, USA
- SeeQC Inc., Elmsford, NY, 10523, USA
| | - Sean R Cheng
- Raytheon BBN Technologies, Cambridge, MA, 02138, USA
- Harvard University, Cambridge, MA, 02138, USA
| | - Rich Lazarus
- Raytheon BBN Technologies, Cambridge, MA, 02138, USA
| | - Oleg Mukhanov
- HYPRES, Inc., Elmsford, NY, 10523, USA
- SeeQC Inc., Elmsford, NY, 10523, USA
| | - Karl K Berggren
- Massachussetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | | | - Thomas A Ohki
- Raytheon BBN Technologies, Cambridge, MA, 02138, USA
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Aradhya SV, Rowlands GE, Oh J, Ralph DC, Buhrman RA. Nanosecond-Timescale Low Energy Switching of In-Plane Magnetic Tunnel Junctions through Dynamic Oersted-Field-Assisted Spin Hall Effect. Nano Lett 2016; 16:5987-5992. [PMID: 27327619 DOI: 10.1021/acs.nanolett.6b01443] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate fast-pulse switching of in-plane-magnetized magnetic tunnel junctions (MTJs) within 3-terminal devices in which spin-transfer torque is applied to the MTJ by the giant spin Hall effect. We measure reliable switching, with write error rates down to 10-5, using current pulses as short as just 2 ns in duration. This represents the fastest reliable switching reported to date for any spin-torque-driven magnetic memory geometry and corresponds to a characteristic time scale that is significantly shorter than predicted possible within a macrospin model for in-plane MTJs subject to thermal fluctuations at room temperature. Using micromagnetic simulations, we show that in the three-terminal spin-Hall devices the Oersted magnetic field generated by the pulse current strongly modifies the magnetic dynamics excited by the spin-Hall torque, enabling this unanticipated performance improvement. Our results suggest that in-plane MTJs controlled by Oersted-field-assisted spin-Hall torque are a promising candidate for both cache memory applications requiring high speed and for cryogenic memories requiring low write energies.
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Affiliation(s)
- S V Aradhya
- Cornell University , Ithaca, New York 14853, United States
| | - G E Rowlands
- Cornell University , Ithaca, New York 14853, United States
| | - J Oh
- Cornell University , Ithaca, New York 14853, United States
| | - D C Ralph
- Cornell University , Ithaca, New York 14853, United States
- Kavli Institute at Cornell , Ithaca, New York 14853, United States
| | - R A Buhrman
- Cornell University , Ithaca, New York 14853, United States
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Abstract
A direct measurement of the potential energy surface that characterizes individual chemical bonds in complex materials has fundamental significance for many disciplines. Here, we demonstrate that the energy profile for metallic single-atom contacts and single-molecule junctions can be mapped by fitting ambient atomic force microscope measurements carried out in the near-equilibrium regime to a physical, but simple, functional form. We extract bond energies for junctions formed through metallic bonds as well as metal-molecule link bonds from atomic force microscope data and find that our results are in excellent quantitative agreement with density functional theory based calculations for exemplary junction structures. Furthermore, measurements from a large number of junctions can be collapsed to a single, universal force-extension curve, thus revealing a surprising degree of similarity in the overall shape of the potential surface that governs these chemical bonds. Compared to previous studies under ambient conditions where analysis was confined to trends in rupture force, our approach significantly expands the quantitative information extracted from these measurements, particularly allowing analysis of the trends in bond energy directly.
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Affiliation(s)
- Sriharsha V Aradhya
- Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York, United States
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Aradhya SV, Venkataraman L. Single-molecule junctions beyond electronic transport. Nat Nanotechnol 2013; 8:399-410. [PMID: 23736215 DOI: 10.1038/nnano.2013.91] [Citation(s) in RCA: 459] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 04/22/2013] [Indexed: 05/21/2023]
Abstract
The idea of using individual molecules as active electronic components provided the impetus to develop a variety of experimental platforms to probe their electronic transport properties. Among these, single-molecule junctions in a metal-molecule-metal motif have contributed significantly to our fundamental understanding of the principles required to realize molecular-scale electronic components from resistive wires to reversible switches. The success of these techniques and the growing interest of other disciplines in single-molecule-level characterization are prompting new approaches to investigate metal-molecule-metal junctions with multiple probes. Going beyond electronic transport characterization, these new studies are highlighting both the fundamental and applied aspects of mechanical, optical and thermoelectric properties at the atomic and molecular scales. Furthermore, experimental demonstrations of quantum interference and manipulation of electronic and nuclear spins in single-molecule circuits are heralding new device concepts with no classical analogues. In this Review, we present the emerging methods being used to interrogate multiple properties in single molecule-based devices, detail how these measurements have advanced our understanding of the structure-function relationships in molecular junctions, and discuss the potential for future research and applications.
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Affiliation(s)
- Sriharsha V Aradhya
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
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Aradhya SV, Frei M, Halbritter A, Venkataraman L. Correlating structure, conductance, and mechanics of silver atomic-scale contacts. ACS Nano 2013; 7:3706-12. [PMID: 23521342 DOI: 10.1021/nn4007187] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We measure simultaneously force and conductance of Ag metal point-contacts under ambient conditions at room temperature. We observe the formation of contacts with a conductance close to 1 G0, the quantum of conductance, which can be attributed to a single-atom contact, similar to those formed by Au. We also find two additional conductance features at ∼0.4 G0 and ∼1.3 G0, which have been previously ascribed to contacts with oxygen contaminations. Here, using a conductance cross-correlation technique, we distinguish three different atomic-scale structural motifs and analyze their rupture forces and stiffness. Our results allow us to assign the ∼0.4 G0 conductance feature to an Ag-O-Ag contact and the ∼1.3 G0 feature to an Ag-Ag single-atom contact with an oxygen atom in parallel. Utilizing complementary information from force and conductance, we thus demonstrate the correlation of conductance with the structural evolution at the atomic scale.
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Affiliation(s)
- Sriharsha V Aradhya
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, United States
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Meisner JS, Ahn S, Aradhya SV, Krikorian M, Parameswaran R, Steigerwald M, Venkataraman L, Nuckolls C. Importance of Direct Metal−π Coupling in Electronic Transport Through Conjugated Single-Molecule Junctions. J Am Chem Soc 2012; 134:20440-5. [DOI: 10.1021/ja308626m] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jeffrey S. Meisner
- Department of Chemistry, Columbia University, New York, New York 10027, United
States
| | - Seokhoon Ahn
- Department of Chemistry, Columbia University, New York, New York 10027, United
States
| | - Sriharsha V. Aradhya
- Department of Applied
Physics
and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Markrete Krikorian
- Department of Chemistry, Columbia University, New York, New York 10027, United
States
| | - Radha Parameswaran
- Departments of Chemistry and Physics, Barnard College, New York, New York 10027, United States
| | - Michael Steigerwald
- Department of Chemistry, Columbia University, New York, New York 10027, United
States
| | - Latha Venkataraman
- Department of Applied
Physics
and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Colin Nuckolls
- Department of Chemistry, Columbia University, New York, New York 10027, United
States
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Aradhya SV, Frei M, Hybertsen MS, Venkataraman L. Van der Waals interactions at metal/organic interfaces at the single-molecule level. Nat Mater 2012; 11:872-6. [PMID: 22886066 DOI: 10.1038/nmat3403] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 07/18/2012] [Indexed: 05/21/2023]
Abstract
Van der Waals (vdW) interaction, and its subtle interplay with chemically specific interactions and surface roughness at metal/organic interfaces, is critical to the understanding of structure-function relations in diverse areas, including catalysis, molecular electronics and self-assembly. However, vdW interactions remain challenging to characterize directly at the fundamental, single-molecule level both in experiments and in first principles calculations with accurate treatment of the non-local, London dispersion interactions. In particular, for metal/organic interfaces, efforts so far have largely focused on model systems consisting of adsorbed molecules on flat metallic surfaces with minimal specific chemical interaction. Here we show, through measurements of single-molecule mechanics, that pyridine derivatives can bind to nanostructured Au electrodes through an additional binding mechanism beyond the chemically specific N-Au donor-acceptor bond. Using density functional theory simulations we show that vdW interactions between the pyridine ring and Au electrodes can play a key role in the junction mechanics. These measurements thus provide a quantitative characterization of vdW interactions at metal/organic interfaces at the single-molecule level.
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Affiliation(s)
- Sriharsha V Aradhya
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
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Ahn S, Aradhya SV, Klausen RS, Capozzi B, Roy X, Steigerwald ML, Nuckolls C, Venkataraman L. Electronic transport and mechanical stability of carboxyl linked single-molecule junctions. Phys Chem Chem Phys 2012; 14:13841-5. [PMID: 22850823 DOI: 10.1039/c2cp41578j] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We characterize electron transport across Au-molecule-Au junctions of heterogeneous carboxyl and methyl sulfide terminated saturated and conjugated molecules. Low-bias conductance measurements are performed using the scanning tunneling microscopy based break-junction technique in the presence of solvents and at room temperature. For a series of alkanes with 1-4 carbon atoms in the hydrocarbon chain, our results show an exponential decrease in conductance with increasing molecule length characterized by a decay constant of 0.9 ± 0.1 per methylene group. Control measurements in pH 11 solutions and with COOMe terminations suggest that the carboxylic acid group binds through the formation of a COO(-)-Au bond. Simultaneous measurements of conductance and force across these junctions yield a rupture force of 0.6 ± 0.1 nN, comparable to that required to rupture a Au-SMe bond. By establishing reliable, in situ junction formation, these experiments provide a new approach to probe electronic properties of carboxyl groups at the single molecule level.
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Affiliation(s)
- Seokhoon Ahn
- Department of Chemistry, Columbia University, New York, NY, USA
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Aradhya SV, Meisner JS, Krikorian M, Ahn S, Parameswaran R, Steigerwald ML, Nuckolls C, Venkataraman L. Dissecting contact mechanics from quantum interference in single-molecule junctions of stilbene derivatives. Nano Lett 2012; 12:1643-1647. [PMID: 22352939 DOI: 10.1021/nl2045815] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Electronic factors in molecules such as quantum interference and cross-conjugation can lead to dramatic modulation and suppression of conductance in single-molecule junctions. Probing such effects at the single-molecule level requires simultaneous measurements of independent junction properties, as conductance alone cannot provide conclusive evidence of junction formation for molecules with low conductivity. Here, we compare the mechanics of the conducting para-terminated 4,4'-di(methylthio)stilbene and moderately conducting 1,2-bis(4-(methylthio)phenyl)ethane to that of insulating meta-terminated 3,3'-di(methylthio)stilbene single-molecule junctions. We simultaneously measure force and conductance across single-molecule junctions and use force signatures to obtain independent evidence of junction formation and rupture in the meta-linked cross-conjugated molecule even when no clear low-bias conductance is measured. By separately quantifying conductance and mechanics, we identify the formation of atypical 3,3'-di(methylthio)stilbene molecular junctions that are mechanically stable but electronically decoupled. While theoretical studies have envisaged many plausible systems where quantum interference might be observed, our experiments provide the first direct quantitative study of the interplay between contact mechanics and the distinctively quantum mechanical nature of electronic transport in single-molecule junctions.
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Affiliation(s)
- Sriharsha V Aradhya
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, USA
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Frei M, Aradhya SV, Hybertsen MS, Venkataraman L. Linker Dependent Bond Rupture Force Measurements in Single-Molecule Junctions. J Am Chem Soc 2012; 134:4003-6. [DOI: 10.1021/ja211590d] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael Frei
- Department of Applied Physics
and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Sriharsha V. Aradhya
- Department of Applied Physics
and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Mark S. Hybertsen
- Center for Functional Nanomaterials, Brookhaven National Laboratories, Upton, New York 11973,
United States
| | - Latha Venkataraman
- Department of Applied Physics
and Applied Mathematics, Columbia University, New York, New York 10027, United States
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11
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Frei M, Aradhya SV, Koentopp M, Hybertsen MS, Venkataraman L. Mechanics and chemistry: single molecule bond rupture forces correlate with molecular backbone structure. Nano Lett 2011; 11:1518-23. [PMID: 21366230 DOI: 10.1021/nl1042903] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We simultaneously measure conductance and force across nanoscale junctions. A new, two-dimensional histogram technique is introduced to statistically extract bond rupture forces from a large data set of individual junction elongation traces. For the case of Au point contacts, we find a rupture force of 1.4 ± 0.2 nN, which is in good agreement with previous measurements. We then study systematic trends for single gold metal-molecule-metal junctions for a series of molecules terminated with amine and pyridine linkers. For all molecules studied, single molecule junctions rupture at the Au-N bond. Selective binding of the linker group allows us to correlate the N-Au bond-rupture force to the molecular backbone. We find that the rupture force ranges from 0.8 nN for 4,4' bipyridine to 0.5 nN in 1,4 diaminobenzene. These experimental results are in excellent quantitative agreement with density functional theory based adiabatic molecular junction elongation and rupture calculations.
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Affiliation(s)
- Michael Frei
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, United States
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