Simultaneous topographic and elemental chemical and magnetic contrast in scanning tunneling microscopy

1. A method of simultaneously analyzing topographic and elemental/chemical/magnetic data in a scanning tunneling microscope, comprising the steps of:

providing an STM probe with a tip;

providing an X-ray source and a beam chopper for generating chopped X-rays from the X-ray source and directing the chopped X-rays from the X-ray source onto a sample having a surface;

generating a conventional tunneling current component from the X-rays interacting with the sample and directing the conventional tunneling current to a first channel;

generating a second current from the X-rays interacting with the sample and including an elemental/chemical/magnetic characteristic current and directing the second current to a second channel;

separating out the conventional tunneling current for analysis with a lock-in amplifier and filter;

analyzing the conventional tunneling current to output topographic information about the sample surface;

analyzing the second current to output elemental/chemical/magnetic information about the sample; and

analyzing output from the lock-in amplifier by an instrumentation amplifier to determine difference between (a) total current arising from the X-ray beam interacting with the sample and (b) the second current

wherein current input to the filter is operated on by the lock-in amplifier to remove components of the elemental/chemical/magnetic characteristic current, thereby enabling isolation of the topographic information in the first channel.

2. The method as defined in claim 1 wherein a lock-in amplifier is used alone to separate out the elemental/chemical/magnetic current for analysis.

3. The method as defined in claim 1 wherein the filter comprises a unit-gain amplifier and a low-pass filter.

4. The method as defined in claim 1 wherein distance z of the tip from the sample is adjusted to assist in removal of the element/chemical/magnetic characteristic current.

5. A system for simultaneously analyzing topographic and elemental/chemical/magnetic data from a sample in a scanning tunneling microscope, comprising:

an STM probe having a tip;

an X-ray source and a beam chopper for generating a chopped X-ray beam;

a lock-in amplifier operating on an input signal arising from the X-ray beam striking the sample to provide a first signal characteristic of elemental/chemical/magnetic information; and

a filter including an amplifier and a low-pass filter, the filter operating on the input signal to provide a second signal output for analysis of only topographic information wherein the filter comprises, a first circuit segment having an I SXSTM circuit input into an operations amplifier whose output is to a low pass filter and an output to a positive side of an instrumentation amplifier and a second circuit segment in parallel with the first circuit segment having a U OUT circuit input derived from a lock-in amplifier which outputs a signal to an operational amplifier which outputs a second signal to a resistor R 1 which outputs a third signal to a negative side of the instrumentation amplifier and also outputs the second signal to a grounded potentiometer R 2 , the instrumentation amplifier providing a resulting output signal OUT for the filter.

6. The system as defined in claim 5 wherein the STM tip having a plurality of layers including a conducting base tip, an insulating layer disposed on the base tip, a titanium layer on the insulating layer and an outer noble metal layer.

7. The system as defined in claim 6 wherein the conducting base tip comprises PtIr.

8. The system as defined in claim 6 wherein the insulating layer comprises SiO 2 .

9. The system as defined in claim 6 wherein the outer noble metal layer comprises Au.

10. The system as defined in claim 6 wherein the tip comprises a nanoscale conducting apex portion.

11. The system as defined in claim 10 wherein the apex portion is fabricated by FIB.

12. The system as defined in claim 11 further including a nanorotator component for manipulating the tip, thereby enabling fabrication of the apex portion.

13. A system for simultaneously analyzing topographic and elemental/chemical/magnetic data from a sample in a scanning tunneling microscope, comprising:

an STM probe having a tip;

an X-ray source and a beam chopper for generating a chopped X-ray beam;

a lock-in amplifier operating on an input signal arising from the X-ray beam striking the sample to provide a first signal characteristic of elemental/chemical/magnetic information; and

a filter including an amplifier and a low-pass filter, the filter operating on the input signal to provide a second signal output for analysis of only topographic information;

the STM tip having a plurality of layers including a conducting base tip, an insulating layer disposed on the base tip, a titanium layer on the insulating layer and an outer noble metal layer.

14. The system as defined in claim 13 wherein the filter comprises, a first circuit segment having an I SXSTM circuit input into an operations amplifier whose output is to a low pass filter and an output to a positive side of an instrumentation amplifier and a second circuit segment in parallel with the first circuit segment having a U OUT circuit input derived from a lock-in amplifier which outputs a signal to an operational amplifier which outputs a second signal to a resistor R 1 which outputs a third signal to a negative side of the instrumentation amplifier and also outputs the second signal to a grounded potentiometer R 2 , the instrumentation amplifier providing a resulting output signal OUT for the filter.

15. The system as defined in claim 13 wherein conducting base tip comprises PtIr, the insulating layer comprises SiO 2 , the outer noble metal layer comprises Au, and the tip comprises a nanoscale conducting apex portion.

16. The system as defined in claim 13 wherein the apex portion is fabricated by FIB.

17. The system as defined in claim 13 further including a nanorotator component for manipulating the tip, thereby enabling fabrication of the apex portion.