2.3.3.3.53. NXbias_spectroscopy

Status:

base class, 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/… experiment.

In these experiments an electric potential is applied between the (conductive) sample and the probe (tip), and the physical properties (e.g. tunnelling current) is 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:

NXbias_sweep, NXcircuit, NXdata, NXobject, NXpositioner_spm

Structure:

measurement_type: (optional) NX_CHAR

The measurement of the I(V) curve can come in two ways: ...

The measurement of the I(V) curve can come in two ways: 1. Constant spacing: The bias voltage is swept from the start to the end with a constant spacing between the tip and surface. 2. Variable spacing: The bias voltage is swept from the start to the end in a discretized spacing between the tip and surface. (Either an array of voltages, or the steps are defined).

Any of these values: constant_spacing | variadic_spacing

POSITIONER_SPM: (optional) NXpositioner_spm

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

The z-offset is a starting tip position before the sweep starts (typically t ...

The z-offset is a starting tip position before the sweep starts (typically the position of a piezo element).

CIRCUIT: (optional) NXcircuit

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

The time or period is taken by a bias sweep to acquire the data for ...

The time or period is taken by a bias sweep to acquire the data for a single bias sweep point (when the given point or whole sweep is started.).

animation_time: (optional) NX_NUMBER {units=NX_TIME}

The time or period is taken by a bias sweep to be displayed.

measurement_time: (optional) NX_NUMBER {units=NX_TIME}

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

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

indicators_period: (optional) NX_NUMBER {units=NX_TIME}

The time or period is taken by the circuit to indicate the bias sweep voltag ...

The time or period is taken by the circuit to indicate the bias sweep voltage after measuring the voltage.

BIAS_SWEEP: (optional) NXbias_sweep

The bias sweep information.

scan_type: (optional) NX_CHAR ⤆

The type of scan like mesh, spiral, etc. ...

The type of scan like mesh, spiral, etc.

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

sweep_number: (optional) NX_NUMBER

The number of sweeps taken during the bias spectroscopy.

first_settling_time: (optional) NX_NUMBER {units=NX_TIME}

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

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

The time is taken to settle the bias voltage at the desired value. The time (at the last sweep) to settle for the last value of the sweep.

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: (recommended) NX_NUMBER

The z position after the sweeps are done.

total_spectroscopy_time: (recommended) NX_NUMBER {units=NX_TIME}

The total time needed for the entire voltage sweep.

scan_region: (optional) NXobject ⤆

The region of the scan area.

scan_range: (optional) NX_NUMBER {units=NX_ANY}

The range of the scan area.

scan_offset: (optional) NX_NUMBER {units=NX_ANY}

The offset of the scan area in 2D (X and Y) space.

scan_angle_N: (optional) NX_NUMBER {units=NX_ANGLE} ⤆

The N (substring) denotes the angle of the scan area with different physic ...

The N (substring) denotes the angle of the scan area with different physical axes.

linear_sweep: (optional) NXobject ⤆

The linear scan information for scanning of a smaple. ...

The linear scan information for scanning of a smaple.

In this scan type the probe is scanned with a constant velocity across the surface, and parameters are measured along the line.

scan_speed: (optional) NX_NUMBER {units=NX_ANY} ⤆

The speed of the scanner or the probe during the scan.

scan_time: (optional) NX_NUMBER {units=NX_TIME}

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

forward_speed_bias: (optional) NX_NUMBER {units=NX_ANY}

Speed of the scanner or the probe moves forward direction.

backward_speed_bias: (optional) NX_NUMBER {units=NX_ANY}

Speed of the scanner or the probe that moves backward direction.

SCAN_data: (optional) NXdata ⤆

The data that comes from scanning the area.

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/NXbias_spectroscopy.nxdl.xml