Indications for Lifshitz transitions in the nodal-line semimetal ZrSiTe induced by interlayer interaction

Abstract

The layered material ZrSiTe is currently extensively investigated as a nodal-line semimetal with Dirac-like band crossings protected by nonsymmorphic symmetry close to the Fermi energy. A recent infrared spectroscopy study on ZrSiTe under external pressure found anomalies in the optical response, providing hints for pressure-induced phase transitions at ≈4.1 and ≈6.5 GPa. By pressuredependent Raman spectroscopy and x-ray diffraction measurements combined with electronic band structure calculations we find indications for two pressure-induced Lifshitz transitions with major changes in the Fermi surface topology in the absence of lattice symmetry changes. These electronic phase transitions can be attributed to the enhanced interlayer interaction induced by external pressure. Our findings demonstrate the crucial role of the interlayer distance for the electronic properties of layered van der Waals topological materials.Topological materials such as topological insulators [1], Dirac [2], Weyl [3][4][5] or line-node semimetals [6,7] are of great fundamental interest due to their exotic nature of electronic phases, and thus heavily investigated nowadays. They usually exhibit extraordinary material properties, for example, high carrier mobility and unusual magnetoresistance [8][9][10]. Topological non-trivial phases often occur in layered materials with weak interlayer bonding, where the single layers behave rather as isolated two-dimensional (2D) objects, enabling the exfoliation to atomically thin 2D crystals with numerous possible applications [11][12][13][14][15]. Since the forces between the layers of such structures are usually weak, they are highly compressible perpendicular to the layers, and a dimensional crossover from 2D to 3D can be induced by external pressure. Generally, layered materials are prone to pressure-induced phenomena, and electronic topological transitions [16] are expected to be induced [17][18][19] and were suggested to occur in layered BiTeBr [20], BiTeI [21, 22], 1T-TiTe 2 [23], and the group V selenides and tellurides Bi 2 Se 3 , Bi 2 Te 3 , Sb 2 Te 3 [24-27]. "Electronic transitions" in metals were first introduced by Lifshitz in 1960 as transitions where the topology of the Fermi surface (FS) changes as a result of the continuous deformation under high external pressure [16]. Examples for pressure-induced alterations of the FS topology are the conversion of an open Fermi surface, such as * These authors contributed equally.a corrugated cylinder-type Fermi surface typical for layered materials, to a closed one, or the appearance of a new split-off region of the FS. Importantly, the changes in the Fermi surface topology during such a so-called Lifshitz transition are not related to a change in the lattice symmetry [16].In this work we find indications for two Lifshitz transitions in the layered van der Waals material ZrSiTe under external pressure, resulting from the enhanced interlayer interaction. ZrSiTe belongs to the family of compounds ZrXY (X=Si, Ge, Sn and Y =O, S, Se, Te), which are...

Increasing the number of topological nodal lines in semimetals via uniaxial pressure

“…Therefore, the phase transition is thus governed by this particular hopping. It has been previously reported that an increase of interlayer interactions without breaking any crystal symmetry might be responsible of the appearance of Lifshitz transitions in ZiSiTe 17 . Here we find that pressure changes hopping processes within the same Sn-Ba-Sn layer leading to the appearance of a new topological nodal line, without breaking the PT symmetry responsible of the stability of the nodal lines.…”

“…Raman spectroscopy and X-ray diffraction measurements as well as calculations have found that they correspond to Lifshitz transitions, in which the topology of the Fermi surface changes without breaking any lattice symmetry. Interlayer interactions caused by pressure are found to be responsible of these transitions 17 . However, the topological character of these transitions cannot be elucidated from these experiments.…”

NMR determination of Van Hove singularity and Lifshitz transitions in the nodal-line semimetal ZrSiTe

“…Its large region of topologically protected drumhead surface states [13] as well as very large spin Berry curvature and associated spin Hall and Nernst response [14] suggest spintronic and related applications. Suggested changes of Fermi surface topology in this family include a temperature-induced Lifshitz transition in ZrSiSe [15], and a pressure-induced Lifshitz transition in ZrSiTe [16] as well as indications of a photoinduced phonon driven transformation [17].…”

“…DFT calculations were also carried out using the Perdew-Burke-Ernzerhof (PBE) potential [19] as implemented in the WIEN2K code [20]. Experimental structure parameters a = 3.71 Å, c = 9.51 Å, with Zr z = 0.2238 and Te z = 0.6399, were used [16,21,22] with a cutoff parameter k max = 7/R MT inside the interstitial region. A mesh of 3000 k points was employed for the initial calculations.…”

“…The sharp VHS adjacent to the protected nodal line implies that additional electronic features relying upon the enhanced g(E ) could be engineered into this system [26][27][28][29][30], by tuning E F to the VHS. Tuning could be accomplished by chemical pressure [43], physical pressure or strain [16,44], and light activation [17] with the required energy difference being quite small. This could be another avenue for switching the topological behavior for quantum computing applications.…”