Fano Interference between Bulk and Surface States of a Dirac Semimetal Cd3As2 Nanowire

Abstract

Dirac semimetals possess Fermi-arc surface states, which will be a set of discrete surface subbands in a nanowire due to the quantum confinement effect. Here, we report a tunable Fano effect induced by the interference between the discrete surface states and continuous bulk states of a Dirac semimetal Cd_{3}As_{2} nanowire. The discrete surface bands lead to a zero bias peak in conductance as the Femi level is tuned to across the surface subbands. The Fano resonance results in an asymmetric line shape in the differential conductance dI/dV spectrum. Furthermore, the Fano interference would introduce an additional phase into the Weyl orbits and lead to a modification of the oscillation frequency. The results are valuable for further understanding the exotic quantum transport properties of topological semimetals.

Observation of an Odd-Integer Quantum Hall Effect from Topological Surface States in Cd3As2

“…The three-dimensional (3D) Dirac semimetal Cd 3 As 2 has linear energy dispersion in bulk states and topologically protected surface states [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. This protection is due to the C 4 rotation symmetry that prohibits a gap near the Dirac point [1,2].…”

“…This protection is due to the C 4 rotation symmetry that prohibits a gap near the Dirac point [1,2]. Lots of interesting transport properties have been revealed in 3D Dirac semimetals, such as chiral anomaly induced negative magnetoresistance [9,10], Weyl-orbit related quantum oscillations [13,14], Berry's phase π related Aharonov-Bohm effect [15,16], bulksurface interference induced Fano effect [19], etc. Furthermore, the quantum Hall effect (QHE) in Cd 3 As 2 films has been reported recently [20][21][22][23].…”

Quantum transport in topological semimetals under magnetic fields (II)

“…As an intermediate fermion between Dirac and Weyl fermion, the host semimetal is expected to have different magnetoresistance [268][269][270]. More topics will also be of broad interest, including the quantum transport in magnetic Weyl semimetals [56,[271][272][273][274][275][276][277][278][279], the kagome ferromagnet Fe 3 Sn 2 [280], double-Weyl semimetals [20,281], type-II Weyl semimetals [51,[282][283][284][285][286][287][288][289][290][291], hopflink nodal-line semimetals [292][293][294][295], Aharonov-Bohm effect [296], quasiparticle interference on the surfaces of Weyl semimetals [297][298][299][300] and Fano effect [301], exploring axial-gravitational anomaly through thermoelectrical transport [302].…”

Well-defined Fano effect in the Andreev reflection process of a parallel double-quantum-dot structure

“…is the so-called Fano parameter. In addition, the other quantity also comes into play, i.e., α = e 2 +1 with T b being the electron tunneling ability in the reference channel [45][46][47]. This reflects the complicated nature of the Fano effect in linear AR process.…”