2.3.3.3.209. NXsts

Status:

application definition, extends NXsensor_scan

Description:

Application definition for temperature-dependent IV curve measurements ...

Application definition for temperature-dependent IV curve measurements #2023.19.7 This Nexus file is currently only for STS data, it will be updated to handle the STM image mode in the future with a focus on bias spectroscopy in Scanning Tunneling Microscopy.

In this application definition, times should be specified always together with a UTC offset.

This is the application definition describing temperature (T) dependent current voltage (IV) curve measurements. For this, a temperature is set. After reaching the temperature, a voltage sweep is performed. For each voltage, a current is measured. Then, the next desired temperature is set and an IV measurement is performed. The data can be visualized in a tensor with: I (NXsensor_C, NXsoftware_Read_offset, NXcircuit) parameters: V has (NXsource+offset, NXsoftware_Scan_offset, NXsensor_V, NXcircuit) T has (NXsource, NXsoftware_Scan_offset, NXsensor_T) x has (NXsoftware_Scan_offset) y has (NXsoftware_Scan_offset) z has (NXsoftware_Scan_offset)

Symbols:

No symbol table

Groups cited:

NXamplifier, NXbias_spectroscopy, NXcircuit, NXcollection, NXdata, NXentry, NXenvironment, NXfabrication, NXinstrument, NXiv_bias, NXlockin, NXpositioner_sts, NXprocess, NXsample, NXsensor, NXtransformations

Structure:

ENTRY: (required) NXentry

definition: (required) NX_CHAR

Obligatory value: NXsts

experiment_type: (required) NX_CHAR

Name of the experiment where the application is applicable. ...

Name of the experiment where the application is applicable.

Any of these values: sts | stm

type: (required) NX_CHAR

The equipments and techniques as well as the parameter settings and referenc ...

The equipments and techniques as well as the parameter settings and reference signals are used during the experiments used in Scanning Tunneling Microscopy (STM).

Any of these values: background | reference | sample

entry_identifier: (optional) NX_CHAR

The name of the output file, with the number of scans at the end. (e.g. ...

The name of the output file, with the number of scans at the end. (e.g. 221122_Au_5K00014)

collection_identifier: (required) NX_CHAR

The name of the series output file, which represents only the public part of ...

The name of the series output file, which represents only the public part of the output file. (e.g. 221122_Au_5K)

experiment_identifier: (optional) NX_CHAR

Path to storage of output files. ...

Path to storage of output files. (e.g. Path C:UsersSPM-PEEMDesktopDATA_Nanonis20220711_CreaTec_Service_Benchmarks_LHeNanonis-Session-PMD100-HVHU_CreaTec_Service_PalmaLabBerlin220711)

experiment_description: (optional) NX_CHAR

Descriptive comments for this experiment, added by the experimenter, coming ...

Descriptive comments for this experiment, added by the experimenter, coming from the output file. (e.g. Comment01 SYNC & Filter LP 8order WITHDRAW 600 steps, locked Au(111), 50pA, 100 mV set point, 1mV DCA, 973Hz,138 1st H, -84 2nd H)

INSTRUMENT: (required) NXinstrument

stm_head_temp: (optional) NX_NUMBER {units=NX_TEMPERATURE}

Temperature of STM head. Note: At least one field from stm_head_temperatur ...

Temperature of STM head. Note: At least one field from stm_head_temperature, cryo_bottom_temp and cryo_sheild_temp must be provided.

cryo_bottom_temp: (optional) NX_NUMBER {units=NX_TEMPERATURE}

Temperature of liquid helium cryostat. Note: At least one field from ...

Temperature of liquid helium cryostat. Note: At least one field from stm_head_temperature, cryo_bottom_temp and cryo_sheild_temp must be provided.

cryo_shield_temp: (optional) NX_NUMBER {units=NX_TEMPERATURE}

Temperature of liquid nitrogen shield. Temperature 3 (K) (e.g 78.00000E+0) ...

Temperature of liquid nitrogen shield. Temperature 3 (K) (e.g 78.00000E+0). Note: At least one field from stm_head_temperature, cryo_bottom_temp and cryo_sheild_temp must be provided.

hardware: (optional) NXfabrication

Hardware type used in SPM experiment, includes hardware manufacturers and ...

Hardware type used in SPM experiment, includes hardware manufacturers and type. (e.g. Nanonis BP5e)

software: (optional) NXfabrication

Type of software used in SPM experiments, such as software version serial ...

Type of software used in SPM experiments, such as software version serial number, UI and RT probe release method. (e.g. SW Version Generic 5e – RT Release 10771)

current_amplifier: (optional) NXamplifier

The Amplifier description that improves or helps to determine tunnel curre ...

The Amplifier description that improves or helps to determine tunnel current (current between tip and bias).

lock_in: (optional) NXlockin

status: (optional) NX_CHAR

Status of Lock-in device whether while performing the experiment

modulation_signal: (optional) NX_CHAR {units=NX_VOLTAGE}

This is the signal on which the modulation (sine) will be added.

modulation_frequency: (required) NX_NUMBER {units=NX_FREQUENCY}

The signal is modulated by adding the frequency of the sine modulation. ...

The signal is modulated by adding the frequency of the sine modulation. The modulation frequency spans can be from 10 mHz to 40 kHz, corresponding to the output filter cut-off range. When dealing with harmonics, it’s essential to ensure that the harmonic frequencies remain below ~100 kHz, which aligns with the input filter cut-off. Be mindful that hardware filters might impact the amplitude as the signal approaches their cut-off frequencies.” (e.g. 973E+0)

modulation_amplitude: (required) NX_NUMBER

The amplitude (in physical units of modulated signal) of the sine modulation.

demodulated_signal: (optional) NX_CHAR

The input signal (STS signal) will be demodulated, in order to determine ...

The input signal (STS signal) will be demodulated, in order to determine the amplitude and phase at the frequency set in the Frequency field or harmonics, such as current, bias, et.al.

harmonic_order_N: (required) NX_NUMBER

N denotes 1 or 2. The order of the harmonic oscillation to be detected i ...

N denotes 1 or 2. The order of the harmonic oscillation to be detected in the demodulated signal should be considered relative to the modulation frequency. When dealing with higher harmonics, it’s essential to ensure that their frequencies do not surpass the analogue signal bandwidth (e.g. harmonic_order_1).

ref_phase_N: (optional) NX_NUMBER

Reference phase for the sine on the demodulated signal with respect to t ...

Reference phase for the sine on the demodulated signal with respect to the modulation signal. The determined phase is displayed with respect to the reference phase.

lock_in_data_flip_number: (required) NX_NUMBER

sample_bias: (required) NXiv_bias

Bias voltage applied to the sample.

bias: (required) NX_NUMBER {units=NX_VOLTAGE}

Applied a voltage between tip and sample.

bias_calibration: (required) NX_NUMBER

bias_offset: (required) NX_NUMBER {units=NX_VOLTAGE}

output_cabling: (optional) NXcircuit

piezo_config: (optional) NXcollection

Configuration for piezoelectric scanner used to move tip along X and Y dir ...

Configuration for piezoelectric scanner used to move tip along X and Y direction. The material of the Piezoelectric scanner composed of polycrystalline solids and sensitive to applied voltage.

active_calib: (required) NX_CHAR

The name of calibration type. (e.g. LHe)

calib_N: (optional) NX_NUMBER

N denotes X or Y or Z. There are three parameters in the X, Y, and Z dir ...

N denotes X or Y or Z. There are three parameters in the X, Y, and Z directions, along with three available controls: Calibration (m/V), Range (m), and HV gain. Only two of these parameters are required to define the calibration. Consequently, when any value is changed, one of the other values will be automatically updated. (e.g. calib_X = 3.8E-9)

hv_gain_N: (optional) NX_NUMBER

N denotes X or Y or Z. In some systems, there is an HV gain readout feat ...

N denotes X or Y or Z. In some systems, there is an HV gain readout feature. For these systems, the HV gain should be automatically adjusted whenever the gain is changed at the high voltage amplifier. (e.g. 14.5)

tilt_N: (optional) NX_NUMBER {units=NX_ANGLE}

N denotes X or Y. There are 2 parameters in X and Y directions, and tilt ...

N denotes X or Y. There are 2 parameters in X and Y directions, and tilt needs to be adjusted according to the actual surface. (in degrees, first order correction).

curvature_radius_N: (optional) NX_NUMBER {units=NX_LENGTH}

N denotes X or Y. There are 2 parameters in X and Y directions. (can be ...

N denotes X or Y. There are 2 parameters in X and Y directions. (can be set approximately to the length of the piezotube).

2nd_order_corr_N: (optional) NX_NUMBER

N denotes X or Y. There are 2 parameters in X and Y directions. If you k ...

N denotes X or Y. There are 2 parameters in X and Y directions. If you know them, you can enter the 2nd order piezo characteristics to compensate for it. The following equation shows the interpretation of the 2nd order correction parameter: For the X-piezo: “Ux = 1/cx · X + cxx · X2” with units: [V] = [V/m] · [m] + [V/m2] · [m2] where cx is the calibration of the piezo X and cxx is the 2nd order correction. (V/m^2). (e.g. 0E+0)

drift_N: (optional) NX_NUMBER

N denotes X, Y or Z. There are 3 parameters in X, Y and Z directions. De ...

N denotes X, Y or Z. There are 3 parameters in X, Y and Z directions. Define the drift speed for all three axes. When the compensation is on, the piezos will start to move at that speed. (e.g. 0E+0)

drift_correction_status: (required) NX_BOOLEAN

Use the button to enable or disable the drift compensation. (e.g. FALSE)

ENVIRONMENT: (required) NXenvironment

An environmental setup to measure the tunneling current due to different t ...

An environmental setup to measure the tunneling current due to different tip- sample biases.

current_sensor: (optional) NXsensor

current: (required) NX_NUMBER {units=NX_CURRENT}

This is set-point of tip current (in the constant current mode should ...

This is set-point of tip current (in the constant current mode should be equal to set-point, in the constant height mode means the real tunnelling current between tip and sample).

current_calibration: (required) NX_NUMBER {units=NX_CURRENT}

Value of calibration that comes as A/V. The value for this concept can ...

Value of calibration that comes as A/V. The value for this concept can be read as current per unit voltage.

current_offset: (required) NX_NUMBER {units=NX_CURRENT}

current_gain: (required) NX_NUMBER {units=NX_UNITLESS}

calibration_time: (optional) NX_DATE_TIME

value: (optional) NX_NUMBER

position: (required) NXpositioner_sts

Clarify the frame laboratory frame.

x: (optional) NX_NUMBER {units=NX_LENGTH}

The scanning area in x position in the frame. (e.g. -890.53E-12)

y: (optional) NX_NUMBER {units=NX_LENGTH}

The scanning area in y position in the frame. (e.g. 29.6968E-9)

z: (optional) NX_NUMBER {units=NX_LENGTH}

The scanning area in z position in the frame. (e.g. 130.5E-9)

z_controller: (required) NXcollection

z: (required) NX_NUMBER {units=NX_LENGTH}

Indicate the relative tip position z between tip and sample. The tip ...

Indicate the relative tip position z between tip and sample. The tip position can also be varied when the z_controller is not running. (e.g. 130.5E-9)

sweep_control: (required) NXcollection

bias_spectroscopy: (optional) NXbias_spectroscopy

integration_time: (required) NX_NUMBER {units=NX_TIME}

Time during which the spectroscopy data are acquired and averaged. (e.g. 150E-6)

number_of_sweeps: (required) NX_NUMBER

Number of sweeps to measure and average. (e.g. 100)

sweep_start: (required) NX_NUMBER {units=NX_VOLTAGE}

The start bias values of the sweep. (e.g. -300E-3)

sweep_end: (required) NX_NUMBER {units=NX_VOLTAGE}

The end bias values of the sweep. (e.g. 300E-3)

num_pixel: (required) NX_NUMBER

The sweep number of points is defined as the maximum spectrum resolu ...

The sweep number of points is defined as the maximum spectrum resolution, which is equal to the bias sweep window divided by the number of pixels. (e.g. 4096)

z_avg_time: (required) NX_NUMBER {units=NX_TIME}

The Z position is recorded and averaged for a certain duration both ...

The Z position is recorded and averaged for a certain duration both before and after the sweep. After the initial Z averaging time, if “Z-Controller to Hold” is selected, the Z-Controller is set to hold mode, and the tip is positioned at the previously averaged Z position (adjusted by the Z offset). (e.g. 100E-3)

circuit: (optional) NXcollection

rt_frequency: (required) NX_NUMBER {units=NX_FREQUENCY}

The bandwidth of the Hardware and/or Software is instrument specific ...

The bandwidth of the Hardware and/or Software is instrument specific. For example, Nanonis Generic 5 has ‘RT Frequency’ (e.g. 20E+3).

signals_oversampling: (required) NX_NUMBER

The Signals Period represents the rate at which signals are transfer ...

The Signals Period represents the rate at which signals are transferred to the host computer, which operates the control software. This rate may be 10 times lower than the sampling rate, as the real-time engine internally oversamples the signal. If desired, you may have the option to reduce the oversampling to 1, enabling higher frequency resolution in the Spectrum Analyzer. (e.g. 10)

acquisition_period: (optional) NX_NUMBER {units=NX_TIME}

The update rate is utilized in various processes, including the Hist ...

The update rate is utilized in various processes, including the History Graph, Auto-Approach, and multiple Programming Interface functions. It may be configured to a 20 ms interval. Any additional timings must strictly be integer multiples of this base value. While it is possible to set these additional timings to different values, the actual timing value will automatically be adjusted to become a multiple of the Acquisition Period. (e.g. 20E-3)

animations_period: (optional) NX_NUMBER {units=NX_TIME}

The update rate of animated graphical indicators, such as graphs and ...

The update rate of animated graphical indicators, such as graphs and sliders, can be adjusted. A normal value may be 40 ms, which corresponds to 25 updates per second. Increasing this period can help reduce the processor load on the graphical user interface, particularly on slower computers. It is important to note that this update rate solely impacts the user interface and does not affect measurements in any manner. (e.g. 20E-3)

indicators_period: (required) NX_NUMBER {units=NX_TIME}

The update rate of digital indicators, such as the numbers displayed ...

The update rate of digital indicators, such as the numbers displayed, can be set to 3 updates per second, equivalent to 300 ms. This interval is sufficient for the user interface and does not impact measurements in any manner. (e.g. 300E-3)

measurements_period: (optional) NX_NUMBER {units=NX_TIME}

The Measurements period determines the integration time required for ...

The Measurements period determines the integration time required for precise measurements, primarily utilized in sweep modules. It is particularly useful for tasks such as recording force-distance curves or cantilever resonances. For swift measurements with small steps, a value of 40 ms is often adequate. For regular use, a range of 300-500 ms may be recommended, but when capturing the resonance of a high-Q cantilever, longer values in the range of several seconds might be necessary. Usually, this parameter does not require manual adjustment within this module, as the sweep modules automatically set this value according to the sweep timings. (e.g. 500E-3)

scan_control: (optional) NXcollection

scan_range: (optional) NX_NUMBER {units=NX_LENGTH}

In STM experiment, the scan range is the coordinate (x,y) along the X ...

In STM experiment, the scan range is the coordinate (x,y) along the X and Y axis from the origin (scan_offset) of the scan area (e.g. 5.000000E-9 5.000000E-9).

scan_offset: (optional) NX_NUMBER {units=NX_LENGTH}

In STM experiment, the scan offset is the position of the tip at the s ...

In STM experiment, the scan offset is the position of the tip at the starting point of scan area. (e.g. -2.354637E-7 1.267476E-)

scan_direction: (optional) NX_CHAR

In STM experiment, the scan direction is the direction from which side ...

In STM experiment, the scan direction is the direction from which side of the sample the tip starts scanning.

Any of these values: down | up | top | bottom

scan_angle: (optional) NX_NUMBER {units=NX_ANGLE}

The angle of scan with the bottom or top side (depends on the scan_dir ...

The angle of scan with the bottom or top side (depends on the scan_direction field) of the sample. (e.g. 0.000E+0).

roi: (required) NXtransformations

frame: (required) NX_CHAR

Also clarify the frame for the ROI of the scan in lab frame, the mid ...

Also clarify the frame for the ROI of the scan in lab frame, the middle of the lab frame is (0, 0), and positive in x means right and in y means up.

circuit: (required) NXcollection

channels_current: (required) NX_CHAR

The scan channels are selected by users. (e.g. (A);Bias (V);Z (m);LI ...

The scan channels are selected by users. (e.g. (A);Bias (V);Z (m);LI Demod 2 X (A);LI Demod 2 Y (A);LI Demod 1 X (A);LI Demod 1 Y (A))

positioner: (required) NXcollection

scanfield: (optional) NX_NUMBER

Configure the scan frame like x position; y position; width; height. ...

Configure the scan frame like x position; y position; width; height. (e.g. 3.11737E-9;29.1583E-9;15E-9;15E-9;0E+0). If the ‘scanfield’ is not considered, use the ‘scan_range’ and ‘scan_offset’ from ‘scan_control’ group

pixels_line: (required) NX_NUMBER

Scan resolution by setting the Lines equal to Pixels. (e.g. 512)

lines: (required) NX_NUMBER

Define the image resolution. (e.g. 512)

speed_forw: (required) NX_NUMBER

Define the scan forward speed in the forward direction. (m/s) (e.g. 11.7187E-9)

speed_backw: (required) NX_NUMBER

Define the scan backward speed in the forward direction. (m/s) (e.g. 11.7187E-9)

resolution_indicators: (optional) NXprocess

stm_head_temp: (optional) NX_NUMBER {units=NX_TEMPERATURE}

Link to target: /NXentry/NXinstrument/stm_head_temp

cryo_bottom_temp: (optional) NX_NUMBER {units=NX_TEMPERATURE}

Link to target: /NXentry/NXinstrument/cryo_bottom_temp

cryo_shield_temp: (optional) NX_NUMBER {units=NX_TEMPERATURE}

Link to target: /NXentry/NXinstrument/temp_cryo_shield

modulation_signal: (optional) NX_CHAR {units=NX_VOLTAGE}

Link to target: /NXentry/NXinstrument/NXlock_in/modulation_signal

integration_time: (required) NX_NUMBER {units=NX_TIME}

number_of_sweeps: (optional) NX_NUMBER {units=NX_UNITLESS}

sweep_start: (required) NX_NUMBER {units=NX_VOLTAGE}

sweep_end: (required) NX_NUMBER {units=NX_VOLTAGE}

num_pixel: (required) NX_NUMBER

z_avg_time: (required) NX_NUMBER {units=NX_TIME}

rt_frequency: (required) NX_NUMBER {units=NX_FREQUENCY}

signals_oversampling: (required) NX_NUMBER

acquisition_period: (optional) NX_NUMBER {units=NX_TIME}

animations_period: (optional) NX_NUMBER {units=NX_TIME}

indicators_period: (required) NX_NUMBER {units=NX_TIME}

measurements_period: (optional) NX_NUMBER {units=NX_TIME}

reproducibility_indicators: (optional) NXprocess

bias: (required) NX_NUMBER {units=NX_VOLTAGE}

Link to target: /NXentry/NXinstrument/NXsample_bias/bias

current: (required) NX_NUMBER {units=NX_CURRENT}

Link to target: /NXentry/NXinstrument/NXenvironment/NXcurrent_sensor/current

bias_calibration: (required) NX_NUMBER {units=NX_UNITLESS}

Link to target: /NXentry/NXnstrument/NXsample_bias/bias_calibration

bias_offset: (required) NX_NUMBER {units=NX_VOLTAGE}

Link to target: /NXentry/NXinstrument/NXsample_bias/bias_offset

current_calibration: (required) NX_NUMBER {units=NX_CURRENT}

current_offset: (required) NX_NUMBER {units=NX_CURRENT}

current_gain: (required) NX_NUMBER {units=NX_UNITLESS}

z_offset: (required) NX_NUMBER {units=NX_LENGTH}

settling_time: (optional) NX_NUMBER {units=NX_TIME}

z_control_hold: (optional) NX_BOOLEAN

final_z: (optional) NX_NUMBER {units=NX_LENGTH}

first_settling_time: (optional) NX_NUMBER {units=NX_TIME}

end_settling_time: (optional) NX_NUMBER {units=NX_TIME}

z_control_time: (optional) NX_NUMBER {units=NX_TIME}

max_slew_rate: (optional) NX_NUMBER {units=NX_ANY}

backward_sweep: (optional) NX_NUMBER {units=NX_ANY}

z_controller_name: (optional) NX_CHAR

z_controller_status: (optional) NX_BOOLEAN

z_controller_setpoint: (optional) NX_NUMBER {units=NX_CURRENT}

y_control_p_gain: (optional) NX_NUMBER

z_control_i_gain: (optional) NX_NUMBER

z_control_time_const: (optional) NX_NUMBER {units=NX_TIME}

z_control_tip_lift: (optional) NX_NUMBER {units=NX_LENGTH}

z_control_switchoff_delay: (optional) NX_NUMBER {units=NX_TIME}

sample: (optional) NXsample

This describes the sample and its properties, as well as constraints that ar ...

This describes the sample and its properties, as well as constraints that are applied to the sample before scanning.

sample_prep_descripton: (required) NX_CHAR

At this moment no base class available that can track entire sample preparation.

DATA: (required) NXdata

This NXdata should contain separate fields for the current values at differe ...

This NXdata should contain separate fields for the current values at different temperature setpoints, for example current_at_100C. There should also be two more fields called temperature and voltage containing the setpoint values. There should also be a field with an array of rank equal to the number of different temperature setpoints and each child’s dimension equal to the number of voltage setpoints. axes: bias_calc signals: li_demod_[1;2]_[X/Y]_[-;bwd;filt;bwd_filt] current_[-;bwd;filt;bwd_filt] temperature

single_point: (optional) NXdata

Plot for a single point (x,y) with I vs. V curve.

line_scan: (optional) NXdata

Line scan with multiple I vs. V curves for different single (x,y) co-ordinates.

alternative_plot: (optional) NXdata

Plot for current(I) curve in the 2D space of (position(x), bias(V)) which ca ...

Plot for current(I) curve in the 2D space of (position(x), bias(V)) which can be derived from the line_scan plot.

mesh_scan: (optional) NXdata

Mesh scan with 2D slices of the above alternative plot for other y co-ordinates.

Hypertext Anchors

List of hypertext anchors for all groups, fields, attributes, and links defined in this class.

NXDL Source:

https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/contributed_definitions/NXsts.nxdl.xml