Scanning tunneling microscope

A method for operating a microscope apparatus which includes a scanning tunneling microscope (STM) and an optical microscope, the microscope apparatus further including a sample table on which a sample to be mounted and an STM unit for STM measurement enclosed by an enclosing member supported by a body portion of the optical microscope, said enclosing member being at the optical microscope side, said STM unit including an STM probe which is constantly located within a vision of field of the optical microscope, the method comprising the steps of:

• observing the sample by means of said optical microscope, for selecting a particular point of said sample to be measured by the scanning tunneling microscope;
• moving the STM probe to the particular point of said sample;
• causing said enclosing member and said sample table to contact with each other such that said enclosing member encloses a sample portion when the STM probe is brought close to the sample;
• and thereafter
• performing an STM measurement with said microscope apparatus.

A scanning tunneling microscope for investigating a surface of a sample, comprising:

• an STM unit including a probe for detecting a tunnel current, said probe having an axis, movement means for supporting and moving said probe along the surface of the sample, and an enclosing member disposed around said probe and said movement means;
• an optical system for preliminarily observing the surface of the sample for locating a portion of the sample which is to be subjected to STM measurement by said STM unit, said optical system including an objective lens having an optical axis,
• a table for mounting the sample thereon, said table having an axis passing through the sample;
• holding means for holding both said STM unit and said objective lens, said holding means including means for bringing the axis of said probe and the optical axis of said objective lens into substantial coincidence with the axis of said table;
• and
• means for moving at least one of said STM unit and said table relative to each other, only when said axis of said probe is brought into coincidence with the axis of said table, so that said table contacts with said enclosing member to provide a closed space surrounding the sample and said probe, said movement means including a cylindrical piezoelectric actuator and an optically transparent member provided at an end portion of said cylindrical piezoelectric actuator, and said objective lens being disposed within said cylindrical piezoelectric actuator.