Towards Automatic Nanomanipulation at the Atomic Scale

Transcription

1 Towards Automatic Nanomanipulation at the Atomic Scale Bernd Schütz Department of Computer Science University of Hamburg, Germany

2 Department of Computer Science Outline Introduction System Overview Workpackages 1. integration of nm into an STM-Measurementsystem 2. segmentation/labelling of atoms and molecules 3. navigation/calibration 4. manipulation skills 5. planning/simulation Outlook Towards Automatic Nanomanipulation at the Atomic Scale 1

3 Department of Computer Science Introduction Definition: Manipulation of nanometer size objects with a nanometer size tool-tip with (sub)nanometer precision. Application: manual (scan manipulate scan) cycle Motivation: Nanomanipulation will soon be a standard preparation technique for experiments in physical and biological science. automation of nanomanipulation mandatory Towards Automatic Nanomanipulation at the Atomic Scale 2

4 Department of Computer Science Introduction Tools Atomic Force Microscope (AFM) manipulation of nanoparticles push, pull, pick and place, bend, twist etc. Scanning Tunneling Microscope (STM) manipulation at the atomic scale repulsive, attractive and vertical mode special tools integrated into a microscope Towards Automatic Nanomanipulation at the Atomic Scale 3

5 Department of Computer Science Introduction STM Manipulation Modes repulsive mode (pure pushing) constant current mode TIP F Adsorbat Surface attractive mode (pure pulling) constant current mode Adsorbat F TIP Surface vertical mode voltage pulse to attain atom to tip move in imaging mode voltage pulse to attain atom to surface F TIP Adsorbat TIP F TIP Surface Towards Automatic Nanomanipulation at the Atomic Scale 4

6 Department of Computer Science Introduction Advanced User Interfaces several user interfaces intended for manual nanomanipulation under development features: advanced graphics haptic device and reliable force feedback teleoperation contact models, modeling of nanoobjects drift compensation designed for ambiant AFM Towards Automatic Nanomanipulation at the Atomic Scale 5

7 Department of Computer Science Introduction Automation in Nanomanipulation manipulating nanoparticles with an AFM first steps towards automation CAD-models of nanostructures drift calculation manipulation at atomic scale with a STM Autonomous Atom Assembler (AAA) tool for automatic positioning of tens of single atoms rule-based path planning no drift compensation Michigan State University National Institute of Standards and Technology Towards Automatic Nanomanipulation at the Atomic Scale 6

8 Department of Computer Science Where we are Introduction System Overview Workpackages 1. integration of nm into an STM-Measurementsystem 2. segmentation/labelling of atoms and molecules 3. navigation/calibration 4. manipulation skills 5. planning/simulation Outlook Towards Automatic Nanomanipulation at the Atomic Scale 7

9 Department of Computer Science System Overview Automatic Manipulation of Atomic Structures in Hamburg (AMASH) tool for automatic nanomanipulation at atomic scale manual manipulation and user intervention possible anytime target description via graphic editor or algorithmic description rule-based pathplanner open-end knowledge base Towards Automatic Nanomanipulation at the Atomic Scale 8

10 Department of Computer Science System Overview System Overview User Interface visualization control haptic Task Database Strategy Recognition Measurement Planning Image Computing Knowledge Base Skill Model Servo Controller Nanomanipulation Sensing Towards Automatic Nanomanipulation at the Atomic Scale 9

11 Department of Computer Science Workpackages 1. enhanced user interface & STM 2. segmentation/labelling of atoms and molecules 3. navigation/calibration 4. manipulation skills 5. planning/simulation Towards Automatic Nanomanipulation at the Atomic Scale 10

12 Department of Computer Science Workpackage 1 Enhanced User Interface & AMASH nanomanipulator from the University of North Carolinas (UNC) nanomanipulator-project: enhanced 3D visualization system haptic control system force-feedback-driven manual manipulation basic manipulation skills supports teleoperation full source code available to us Towards Automatic Nanomanipulation at the Atomic Scale 11

13 Department of Computer Science Workpackage 1 UNC nm & AMASH User Interface Visualization Control Haptic Task Database Strategy Recognition Measurement Planning Image Computing Knowledge Base Skill Model Servo Controller Nanomanipulation Sensing green darkgreen covered by the nanomanipulator covered by the microscope Towards Automatic Nanomanipulation at the Atomic Scale 12

14 Department of Computer Science Workpackage 1 Hamburg UHV LT-STM & AMASH Ultra High Vacuum (UHV) Low Temperature down to 6K Magnetic field 6T Contamination rate < 1 adsobate per 500x500nm per week Fe evaporator Towards Automatic Nanomanipulation at the Atomic Scale 13

15 Department of Computer Science Workpackage 1 Measurement System TOPS II measurement system from WA Technologie attached to: UHV LT-STM (1) specification see above UHV LT-AFM temperature down to 10 K atomic resolution UHV LT-STM (2) temperature down to 300 mk magnetic field 14 T full source code available Towards Automatic Nanomanipulation at the Atomic Scale 14

16 Department of Computer Science Workpackage 1 UNC nm & HH UHV LT-STM both user interfaces (primary and nm) should run in parallel at least two secondary user interfaces (nms) should be able to run in parallel the architecture of the UNC nm provides an excellent basis for AMASH Towards Automatic Nanomanipulation at the Atomic Scale 15

17 Department of Computer Science Workpackage 1 Integration of nm & STM Image generation Geometry Buttons Events User Interface Commands/ queries TCP/IP Host System Linux PC Transputer System ISA Expansioncard Store Tops T805 16M T805 2M Screen Analog Electronics & HV Amplifier Display nanomanipulator Positions Forces Phantom Samples/ responses TOPS System Body Head T805 1M T414 1M External Expansion DAC ADC DAC (XYZ)shift bias shift captured data (XYZ)scale & position bias scale & value XYZ sensor STM Tunneling current I + Sample Positoning device for X, Y and Z Y X Z only minor changes of the nm-software Towards Automatic Nanomanipulation at the Atomic Scale 16

18 Department of Computer Science Workpackage 1 Integration of nm & STM Image generation Geometry Buttons Events User Interface Commands/ queries TCP/IP Host System Linux PC Transputer System ISA Expansioncard Store Tops T805 16M T805 2M Screen Analog Electronics & HV Amplifier Display nanomanipulator Positions Forces Phantom Samples/ responses TOPS System Body Head T805 1M T414 1M External Expansion DAC ADC DAC (XYZ)shift bias shift captured data (XYZ)scale & position bias scale & value XYZ sensor STM Tunneling current I + Sample Positoning device for X, Y and Z Y X Z only minor changes of the nm-software the primary user interface of the microscope completely reprogrammed Towards Automatic Nanomanipulation at the Atomic Scale 16

19 Department of Computer Science Workpackage 1 Integration of nm & STM Image generation Geometry Buttons Events User Interface Commands/ queries TCP/IP Host System Linux PC Transputer System ISA Expansioncard Store Tops T805 16M T805 2M Screen Analog Electronics & HV Amplifier Display nanomanipulator Positions Forces Phantom Samples/ responses TOPS System Body Head T805 1M T414 1M External Expansion DAC ADC DAC (XYZ)shift bias shift captured data (XYZ)scale & position bias scale & value XYZ sensor STM Tunneling current I + Sample Positoning device for X, Y and Z Y X Z only minor changes of the nm-software the primary user interface of the microscope completely reprogrammed some changes of the low-level routines of the measurementsystem software also neccessary Towards Automatic Nanomanipulation at the Atomic Scale 16

20 Department of Computer Science Workpackage 1 Requirements for primary user Interface interface for communication with nm via TCP/IP API for controlling the instrument (more flexibility with other microscopes) API for IEEE 488 equipment for full control of instruments environment script language for rapid prototyping of low-level algorithms ability to run instrument in batch mode web-interface for monitoring readouts Towards Automatic Nanomanipulation at the Atomic Scale 17

21 Department of Computer Science Workpackage 1 Results of Integration of nm & UHV LT-STM full power of the nm-system is now available to the STM users manual manipulation is much more comfortable due to haptic device nm-user can access the microscope from all over the world (problem: network latency in manipulation mode) excellent platform for developing automation on the atomic scale Towards Automatic Nanomanipulation at the Atomic Scale 18

22 Department of Computer Science Workpackage 1 Tungsten surface as used for our tests with surface steps and some Fe adsorbat Atoms. The step highlighted by the red and blue line denotes a monolayer step. Towards Automatic Nanomanipulation at the Atomic Scale 19

23 Department of Computer Science Where we are Introduction System Overview Workpackages 1. integration of nm into an STM-Measurementsystem 2. segmentation/labelling of atoms and molecules 3. navigation/calibration 4. manipulation skills 5. planning/simulation Outlook Towards Automatic Nanomanipulation at the Atomic Scale 20

24 Department of Computer Science Workpackage 2 Segmentation/Labelling Robust automatic segmentation/labelling of atoms and molecules: Segmentation: several types of adsorbat atoms STM topographic data on-demand local spectroscopy structural and statistical methods Labelling: atoms: on/beneath the surface molecules: orientation, shape descriptors Towards Automatic Nanomanipulation at the Atomic Scale 21

25 Department of Computer Science Workpackage 3 Navigation/Calibration Navigation/Positioning based on results of image processing specialized software-controller off-line training Calibration consecutive update and recalibration of internal control Calibrated Synthetic Viewing (CSV) approach Drift compensation Kalman filtering restrictive local scan approach Towards Automatic Nanomanipulation at the Atomic Scale 22

26 Department of Computer Science Workpackage 4 Manipulation Skills Hierarchical sensor-based skill library: basic skills positioning tool tip moving tool tip pure pushing, pure pulling attain/reattain adsorbat advanced skills (composed of basic and acvanced skills) moving (attractive repulsive vertical) collision-free path control cleaning area Towards Automatic Nanomanipulation at the Atomic Scale 23

27 Department of Computer Science Workpackage 5 Planning/Simulation Planning rule-based planning knowledge base with a set of rules for every adsorbat error recovery for uncertainty Simulation validating the moves of a path validating the sequence of paths Control scheme adjustable autonomy Towards Automatic Nanomanipulation at the Atomic Scale 24

28 Department of Computer Science Outlook realized combination of nanomanipulator and UHV LT-STM not only an excellent platform for AMASH but also eases the usage of the STM step by step refinement towards automation a working system at every stage of development Towards Automatic Nanomanipulation at the Atomic Scale 25