Electron-phonon interaction and zero-field charge carrier transport in the nodal-line semimetal ZrSiS

Abstract

We study electron-phonon interaction and related transport properties of nodal line semimetal ZrSiS using first-principles calculations. We find that ZrSiS is characterized by a weak electronphonon coupling of the order of 0.1, which is almost energy-independent. Main contribution to the electron-phonon coupling originates from long-wavelength optical phonons, causing no significant renormalization of the electron spectral function. At the charge neutrality point, we find that electrons and holes provide a comparable contribution to the scattering rate. The phonon-limited resistivity calculated within the Boltzmann transport theory is found to be strongly directiondependent with the ratio between out-of-plane and in-plane directions being ρzz/ρxx ∼ 7.5, mainly determined by the anisotropy of carrier velocities. We estimate zero-field resistivity to be ρxx ≈ 12 µΩ·cm at 300 K, which is in good agreement with experimental data. Relatively small resistivity in ZrSiS can be attributed to a combination of weak electron-phonon coupling and high carrier velocities.

Anisotropic Berry phase in the Dirac nodal-line semimetal ZrSiS: The effect of spin-orbit coupling

“…To obtain a quantitative understanding of the oscillation frequencies described above, additional information on the FS is needed. However, the nodal-line semimetal-lic nature of ZrSiS makes its FS structure very sensitive to the exact position of the Fermi level, which is partly the reason for the apparently different FS reported in earlier DFT calculations 16,28,29 . Among the resolvable peaks (γ, β 1 and β 2 ) summarized in Fig.…”

Time-dependent electric transport in nodal loop semimetals

“…where σ i 's (i = x, z) are the Pauli matrices, m ≈ 0.1 − 1 m e (m e is the mass of an electron) is the effective mass [34,44,45], ∆ ≈ 0.1 − 1 eV is the energy scale that defines the nodal loop radius [46,47] and v F ≈ 10 5 −10 6 m/s is the Fermi-velocity in the z direction [44,45]. Diagonalizing the Hamiltonian yields the energy spectrum as E ± (p) = ±ε p with ± the band index and…”

“…It is defined as E z,c = /(ev F τ 2 sc ) for z direction and E x,c = 2m /(e 2 τ 3 sc ) for x direction. The scattering time is estimated as τ sc ∼ 10 −2 − 10 −1 ps [45,66], which implies that the minimal electric field required to observe nonlinear transport is E x/z,c ∼ 10 5 − 10 7 V/m. For E E > E x/z,c , the current changes its slope as a function of the electric field, but an even larger electric field window may be required to obtain the corresponding exponents.…”

Ultrafast relaxation of acoustic and optical phonons in a topological nodal-line semimetal ZrSiS

“…ZrXY family of materials where X = Si, Sn, Ge and Y = S, Se, Te are among the most studied TNSMs due to their high crystal quality and flexibility of the chemical composition [9,10,[27][28][29][30][31][32][33][34][35][36][37][38][39]. Among the ZrXY family of materials, ZrSiS is an especially interesting material, since it possesses linearly dispersing bands extending up to 2 eV, which are free from interference from trivial bands making this material an excellent prospect for studying Dirac physics [27].…”

“…ZrXY family of materials where X = Si, Sn, Ge and Y = S, Se, Te are among the most studied TNSMs due to their high crystal quality and flexibility of the chemical composition [9,10,[27][28][29][30][31][32][33][34][35][36][37][38][39]. Among the ZrXY family of materials, ZrSiS is an especially interesting material, since it possesses linearly dispersing bands extending up to 2 eV, which are free from interference from trivial bands making this material an excellent prospect for studying Dirac physics [27]. Even though several experimental studies have been reported on ZrSiS such as angle-resolved photoemission spectroscopy (ARPES) [9,10,30,37,38], high-field magnetotransport measurements [40,41], scanning tunneling microscopy [42], frequency-independent optical conductivity [43], high carrier mobility [41,44], the experimental and theoretical description of the effect of phonon scattering in electron cooling processes have not been studied so far.…”