Ultrafast terahertz control of extreme tunnel currents through single atoms on a silicon surface

Distinguishing Majorana zero modes from impurity states through time-resolved transport

“…Compared to the MZM and QMS, the broadening of the resonances related to the IS and the consequent faster decay times could be attributed to the impurity-induced hopping disorder and the consequent increased effective tunnel barrier around the impurities. This finding could be utilized in possible detection and identification of the MZM or QMS via ultrafast transport measurements [23][24][25][26][27][28][29][30]84]. In order to estimate a limit for the time scales that one needs to be able to resolve, we refer to the experiment of Mourik et al [10], who found an induced superconducting energy gap of 250μeV.…”

“…In contrast, the nonequilibrium problems are often much richer and more interesting than equilibrium properties [20][21][22]. This is especially relevant when nowaday transport measurements are pushing the temporal resolution to sub-picosecond regime [23][24][25][26][27][28][29][30], and these ultrafast processes can be observed in real time.…”

Terahertz quantum plasmonics at nanoscales and angstrom scales

“…Terahertz scanning tunneling microscope (STM) (THz-STM) is capable of imaging surfaces with atomic spatial resolution and the subpicosecond time resolution (<0.5 ps), much faster than conventional STM system [15,17,19,20,76,77]. The basic principle of THz-STM is quantum tunneling through the gap between the tip and sample resulting from a transient voltage induced by terahertz pulses.…”

“…The strongly enhanced terahertz electric field at the tip apex enables to produce the transient bias voltage with maintaining nanometer spatial resolution. A recent work reports imaging and tunneling spectroscopy of conductive surfaces with atomic resolution (~0.3 nm), which shows the image of ultrafast nonequilibrium tunneling dynamics for individual atoms on a silicon surface [17].…”

“…Over the past decades, advances in the generation of intense terahertz waves have enabled new researches on light-matter interaction. In particular, tabletop systems generating high-power terahertz pulses [1][2][3][4][5][6] provide broad opportunities to study ultrafast dynamics of matters in the nonlinear regime, through resonant and nonresonant coupling [7][8][9][10][11][12][13][14][15][16][17][18]. The low photon energy of terahertz waves allows resonant coupling with direct excitation of low-energy modes such as vibrations of crystal lattices, rotation of molecules, precessions of spins, and internal excitations of bound electron-hole pairs.…”