II. Physikalisches Institut BFachbereich Physik

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Instrumentation

Unsere Arbeitsgruppe verfügt zur Zeit über acht Ultrahochvakuum-Rastertunnelmikroskope (UHV-STMs), darunter ein kombiniertes Rasterkraft-/Rastertunnelmikroskop, sowie einen Transportmessplatz zur Messung von elektrischen Leitfähigkeiten bei 280mK und 10T. Drei STM-Systeme arbeiten bei tiefen Temperaturen (6K, 600mK und 380mK). Im Aufbau befindet sich eine weitere Tieftemperatur-STM Anlage (800mK), sowie ein trockenes STM-System, welches mit einem Pulse-Tube-Kühler arbeitet und 1K erreichen soll. Ein 4-Spitzen-Hochfrequenz-STM (Raumtemperatur, 400ps) befindet sich in der Testphase. Nähere Informationen zu den Systemen erhalten Sie durch Anklicken der Felder.

Tieftemperatur-AFM/STM Anlage (380mK/14T)
Tieftemperatur-Hochfrequenz-STM System (6K/7T max/500mT rotierbar/200ps)
Tieftemperatur Hochfrequenz-JT-STM System (600mK/3T/200ps)
Tieftemperatur STM System (im Aufbau, 800mK)
Trockenes Tieftemperatur-STM System (im Aufbau, 1K)
Raumtemperatur-STM 1
Raumtemperatur-STM 2
Hochfrequenz VT-STM-System (90-400K/120ps)
Transportmesssystem (280mK/10T)
4-Spitzen Hochfrequenz-Rastertunnelmikrospie-System
Wie funktioniert ein Rastertunnelmikroskop?

Kurzer Video-Überblick über die Möglichkeiten und das Funktionsprinzip eines Rastertunnelmikroskops

Publikationen
  1. C. Saunus, J. Raphael Bindel, M. Pratzer, and M. Morgenstern Versatile scanning tunneling microscopy with 120ps time resolution Applied Physics Letters 102, 051601 (2013); doi:10.1063/1.4790180
    [BibTeX] [Abstract] [Download PDF]

    We describe a fully ultra-high vacuum compatible scanning tunneling microscope (STM) optimized for radio-frequency signals. It includes in-situ exchangeable tips adapted to high frequency cabling and a standard sample holder, which offer access to the whole range of samples typically investigated by STM. We demonstrate a time resolution of 120ps using the nonlinear I(V)-characteristic of the surface of highly oriented pyrolithic graphite. We provide atomically resolved images in pulse mode related to a spatially varying nonlinearity of the local density of states of the sample, thus, demonstrating the possible spatial resolution of the instrument in pulse mode. Analysis of the noise reveals that changes in the tunneling junction of 50pA are dynamically detectable at 120ps time resolution.

    @article{:/content/aip/journal/apl/102/5/10.1063/1.4790180,
abstract = {We describe a fully ultra-high vacuum compatible scanning tunneling microscope (STM) optimized for radio-frequency signals. It includes in-situ exchangeable tips adapted to high frequency cabling and a standard sample holder, which offer access to the whole range of samples typically investigated by STM. We demonstrate a time resolution of 120ps using the nonlinear I(V)-characteristic of the surface of highly oriented pyrolithic graphite. We provide atomically resolved images in pulse mode related to a spatially varying nonlinearity of the local density of states of the sample, thus, demonstrating the possible spatial resolution of the instrument in pulse mode. Analysis of the noise reveals that changes in the tunneling junction of 50pA are dynamically detectable at 120ps time resolution.},
added-at = {2015-03-17T00:20:01.000+0100},
author = {Saunus, Christian and Raphael Bindel, Jan and Pratzer, Marco and Morgenstern, Markus},
biburl = {http://www.bibsonomy.org/bibtex/2b1288f492f765ae277a07f424394a19a/institut2b},
description = {Versatile scanning tunneling microscopy with 120ps time resolution},
doi = {10.1063/1.4790180},
eid = {051601},
interhash = {42855c0861bdeef9a0cc9beb945cc8f4},
intrahash = {b1288f492f765ae277a07f424394a19a},
journal = {Applied Physics Letters},
keywords = {morgenstern},
number = 5,
timestamp = {2015-03-17T00:20:01.000+0100},
title = {Versatile scanning tunneling microscopy with 120ps time resolution},
url = {http://scitation.aip.org/content/aip/journal/apl/102/5/10.1063/1.4790180},
volume = 102,
year = 2013
}
  1. T. Mashoff, M. Pratzer, and M. Morgenstern A low-temperature high resolution scanning tunneling microscope with a three-dimensional magnetic vector field operating in ultrahigh vacuum Review of Scientific Instruments 80, 053702 (2009); doi:10.1063/1.3127589
    [BibTeX] [Abstract] [Download PDF]

    We present a low-temperature ultrahigh vacuum (UHV) scanning tunneling microscope setup with a combination of a superconducting solenoid coil and two split-pair magnets, providing a rotatable magnetic field up to 500 mT applicable in all spatial directions. An absolute field maximum of B = 7 T ( 3 T ) can be applied perpendicular (parallel) to the sample surface. The instrument is operated at a temperature of 4.8 K. Topographic and spectroscopic measurements on tungsten carbide and indium antimonide revealed a z -noise of 300 fm pp , which barely changes in magnetic field. The microscope is equipped with a tip exchange mechanism and a lateral sample positioning stage, which allows exact positioning of the tip with an accuracy of 5 µ m prior to the measurement. Additional contacts to the sample holder allow, e.g., the application of an additional gate voltage. The UHV part of the system contains versatile possibilities of in situ sample and tip preparation as well as low-energy electron diffraction and Auger analysis.

    @article{:/content/aip/journal/rsi/80/5/10.1063/1.3127589,
abstract = {We present a low-temperature ultrahigh vacuum (UHV) scanning tunneling microscope setup with a combination of a superconducting solenoid coil and two split-pair magnets, providing a rotatable magnetic field up to 500 mT applicable in all spatial directions. An absolute field maximum of B = 7 T ( 3 T ) can be applied perpendicular (parallel) to the sample surface. The instrument is operated at a temperature of 4.8 K. Topographic and spectroscopic measurements on tungsten carbide and indium antimonide revealed a z -noise of 300 fm pp , which barely changes in magnetic field. The microscope is equipped with a tip exchange mechanism and a lateral sample positioning stage, which allows exact positioning of the tip with an accuracy of 5 µ m prior to the measurement. Additional contacts to the sample holder allow, e.g., the application of an additional gate voltage. The UHV part of the system contains versatile possibilities of in situ sample and tip preparation as well as low-energy electron diffraction and Auger analysis.},
added-at = {2015-03-17T00:26:06.000+0100},
author = {Mashoff, T. and Pratzer, M. and Morgenstern, M.},
biburl = {http://www.bibsonomy.org/bibtex/272e35a9c9a857f14c7eec517b24ec1ca/institut2b},
description = {A low-temperature high resolution scanning tunneling microscope with a three-dimensional magnetic vector field operating in ultrahigh vacuum},
doi = {10.1063/1.3127589},
eid = {053702},
interhash = {6a5603e232e1a9d1641d4628d6d5ba13},
intrahash = {72e35a9c9a857f14c7eec517b24ec1ca},
journal = {Review of Scientific Instruments},
keywords = {morgenstern},
number = 5,
timestamp = {2015-03-17T00:26:06.000+0100},
title = {A low-temperature high resolution scanning tunneling microscope with a three-dimensional magnetic vector field operating in ultrahigh vacuum},
url = {http://scitation.aip.org/content/aip/journal/rsi/80/5/10.1063/1.3127589},
volume = 80,
year = 2009
}