2.3.3.3.81. NXspm_bias_spectroscopy

Status:

base class (contribution), extends NXobject

Description:

A base class for bias spectroscopy to describe the change in the physical proper ...

A base class for bias spectroscopy to describe the change in the physical properties of the sample with respect to the sweep voltage applied on a sample of STM/AFM/… experiments.

In these experiments an electric potential is applied between the (conductive) sample and the probe (tip), and the physical properties (e.g. tunnelling current) are measured as the function of this potential. The potential is varied in so-called voltage sweeps and the corresponding properties are recorded accordingly.

Symbols:

No symbol table

Groups cited:

NXcircuit, NXcoordinate_system, NXdata, NXpid_controller, NXspm_positioner, NXspm_scan_control, NXspm_scan_pattern, NXspm_scan_region

Structure:

measurement_type: (optional) NX_CHAR

The measurement type defines how current is measured under the different input ...

The measurement type defines how current is measured under the different input variables like bias voltage (constant_spacing) or height (variadic_spacing) is applied during the measurement.

Any of these values: constant_spacing | variadic_spacing

identifier_environment: (recommended) NX_CHAR ⤆

Unique identifier for the environment defined by the user or lab. When multipl ...

Unique identifier for the environment defined by the user or lab. When multiple scans are performed in a single environment conditions or settings, the entire scan environment can be differentiated by this identifier. For example, scan on a sample of TiSe2 with layered of evaporated pyrene and annealed at 300K temperature for 5 min process.

SPM_POSITIONER: (optional) NXspm_positioner

Information about the positioner PID (proportional, integral, differential fee ...

Information about the positioner PID (proportional, integral, differential feedback system), offset values, setpoint values and so on, while running bias voltage-tunneling current measurement.

These components position the probe relative to the sample, thus help obtaining maps of the data across the sample surface.

z_controller: (optional) NXpid_controller ⤆

CIRCUIT: (optional) NXcircuit

acquisition_time: (optional) NX_NUMBER {units=NX_TIME} ⤆

The time or period (average) to acquire the data for a single bias sweep point.

animation_time: (optional) NX_NUMBER {units=NX_TIME}

The time or period a bias sweep to be displayed.

measurement_time: (optional) NX_NUMBER {units=NX_TIME}

The time or period taken by the circuit to measure a full bias sweep ...

The time or period taken by the circuit to measure a full bias sweep (duration of the voltage-current measurement measurement).

BIAS_SWEEP: (optional) NXspm_scan_control

The bias sweep scan which is is performed in the scanning probe microscopy ...

The bias sweep scan which is is performed in the scanning probe microscopy experiments.

scan_type: (optional) NX_CHAR ⤆

This combines not only how the voltages are changed, but how the voltage val ...

This combines not only how the voltages are changed, but how the voltage values are correlated to a position across the sample surface, measuring sweeps are each spatial coordinate or mapping the response at constant voltage, etc. For STS experiment, the scan type is usually a single-point scan (trajectory scan).

Obligatory value: linear

number_of_sweeps: (optional) NX_NUMBER

The number of sweeps (a full scan from starting bias to end bias) ...

The number of sweeps (a full scan from starting bias to end bias) taken during the bias spectroscopy.

first_settling_time: (optional) NX_NUMBER {units=NX_TIME}

The initial time taken to settle the bias voltage at the desired value. ...

The initial time taken to settle the bias voltage at the desired value. On each sweep usually, the system takes time to settle to the bias voltage at the next value.

end_settling_time: (optional) NX_NUMBER {units=NX_TIME}

The time (at the last sweep) to settle for the last value of the sweep.

settling_time: (optional) NX_NUMBER {units=NX_TIME}

The time taken to settle the bias voltage at the desired value. On each swee ...

The time taken to settle the bias voltage at the desired value. On each sweep usually, the system takes time to settle the bias voltage at the next value.

max_slew_rate: (optional) NX_NUMBER {units=NX_ANY}

The rate at which the amplifier responds to the voltage change ...

The rate at which the amplifier responds to the voltage change (to reach at the desired value). It defines if the tip movement and voltage sweep are synchronized.

final_z: (optional) NX_NUMBER {units=NX_LENGTH}

The z position after the sweeps are done.

total_spectroscopy_time: (optional) NX_NUMBER {units=NX_TIME}

The total time needed for the entire voltage sweep.

spatial_location: (optional) NXcoordinate_system

The spatial location of the scan points. ...

The spatial location of the scan points. This would be recommended to use if there are multiple bias sweep scans at different locations.

x: (optional) NX_NUMBER {units=NX_LENGTH} ⤆

y: (optional) NX_NUMBER {units=NX_LENGTH} ⤆

z: (optional) NX_NUMBER {units=NX_LENGTH} ⤆

scan_region: (optional) NXspm_scan_region ⤆

The scan region is the area of phase space or sub-phase space where the scan ...

The scan region is the area of phase space or sub-phase space where the scan is performed.

scan_offset_bias: (optional) NX_NUMBER {units=NX_VOLTAGE}

The starting voltage of the bias sweep. The range of voltages for the swee ...

The starting voltage of the bias sweep. The range of voltages for the sweep can be defined with scan voltage offset and scan voltage range (difference between minimum and maximum voltage values in a sweep)

scan_range_bias: (optional) NX_NUMBER {units=NX_VOLTAGE} ⤆

The range of voltages for the sweep can be defined with scan voltage offse ...

The range of voltages for the sweep can be defined with scan voltage offset and scan voltage range (difference between minimum and maximum voltage values in a sweep)

scan_start_bias: (optional) NX_NUMBER {units=NX_VOLTAGE} ⤆

The start of the bias scan voltage.

scan_end_bias: (optional) NX_NUMBER {units=NX_VOLTAGE} ⤆

The end value of the bias scan voltage.

linear_sweep: (optional) NXspm_scan_pattern ⤆

In the linear sweep, the bias voltage is changed linearly from the start val ...

In the linear sweep, the bias voltage is changed linearly from the start value to the end value.

backward_sweep: (optional) NX_BOOLEAN

If the bias voltage sweep is also performed in the opposite direction.

scan_points_bias: (optional) NX_NUMBER ⤆

The number of voltage points per sweep.

step_size_bias: (optional) NX_NUMBER {units=NX_VOLTAGE} ⤆

The step size between the two consecutive bias voltage values during the sweep.

scan_time: (optional) NX_NUMBER {units=NX_TIME}

The time taken by the scanner to scan the entire area.

reset_bias: (optional) NX_BOOLEAN

The reset_bias defines whether the bias voltage should be reset to the sta ...

The reset_bias defines whether the bias voltage should be reset to the starting value after the sweep is completed.

DATA: (optional) NXdata ⤆

The scan data is the data collected during the scan. ...

The scan data is the data collected during the scan. If the scan has several channels or derivatives from the channel data, please duplicate this NXdata group for each.

To define specific current or voltage use DATA and AXISNAME.

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/NXspm_bias_spectroscopy.nxdl.xml