First steps with mesoscoPy

This is a short introduction, so that new users can start measuring quickly using mesoscoPy. Before you start with this code, make sure you have properly installed and set up the Python environment, as explained on [this page](../start/installation.rst).

Module import and database initialisation

The first thing to do is to import mesoscoPy and load a database. If the database does not exist yet, the init_db will first create it and then load. Otherwise, it will simply load it.

import mesoscopy
mesoscopy.init_db('./database.db')

Station initialisation

In the following example, the measurement setup includes two Zurich Instruments’ MFLI lockin amplifiers (serial numbers mf-dev4400 and mf-dev4401), an Oxford Mercury ITC temperature controller (on IP 192.168.0.2) and a Keithley 2614B source-measurement unit (on IP 102.168.0.13). In order to initialise the connection to all these instruments, the basic command will be:

station = mesoscopy.init_station(
    '4400', '4401',
    MercITC_addr='TCPIP::192.168.0.2::7020::SOCKET',
    K2600_addr='TCPIP::192.168.0.13::inst0::INSTR'
)

This will create 4 instruments: station.mf4400, station.mf4401, station.MercuryITC and station.keithley2600. One can list all instruments using:

station.components

Instrument initialisation

mesoscopy.init_smu(
    station,
    mode = ['voltage', 'voltage'],
    limits_v = [20, 50],
    limits_i = [10e-8, 50e-8],
    max_rate = [.28, .28]
)

mesoscopy.init_mfli(
    station,
    freq = 127,
    ampl = .5,
    filterorder = 3
    sensitivity = 3e-3
)

Start measuring

exp = mesoscopy.create_exp(
    experiment_name = 'gate dependence',
    sample_name = 'sample001'
)

xvals = mesoscopy.generate_lin_array(10, -10, step=.1)

mesoscopy.sweep1d(
    station.keithley2600.smua.volt,
    xvals,
    .9,
    station.mf4400.demods[0].sample,
    station.mf4401.demods[0].sample,
    station.keithley2600.smub.curr,
    station.MercuryITC.he3_temp,
    exp=exp,
    measurement_name='sweep Vg1 10V:-10V, I = 50nA, V4400:contacts 1-2, V4401: contacts 3-4, T 300mK'
)

xvals = mesoscopy.generate_lin_array(10, -10, step=.1)
yvals = mesoscopy.generate_lin_array(30, -30, step=.1)

mesoscopy.sweep2d(
    station.keithley2600.smua.volt,
    xvals, .9,
    station.keithley2600.smub.volt,
    yvals, .9,
    station.mf4400.demods[0].sample,
    station.mf4401.demods[0].sample,
    station.keithley2600.smub.curr,
    station.MercuryITC.he3_temp,
    exp=exp,
    measurement_name='sweep Vg1 10V:-10V, Vg2 30V:-30V, I = 50nA, V4400:contacts 1-2, V4401: contacts 3-4, T 300mK'
)

Plot data

import matplotlib.pyplot as plt

x1, y1 = mesoscopy.analysis.load.import_sweep(1)

fig, ax = plt.subplots()

ax.plot(
    x1['keithley_smua_volt'],
    np.real(y1['mf4400_demods0_complex_sample'])/50e-9
)
ax.set_xlabel('$V_{g1}$ (V)')
ax.set_ylabel('$R_{1-2}$ (Ω)')