Optical properties of BiTeBr and BiTeCl

Abstract

We present a comparative study of the optical properties - reflectance, transmission and optical conductivity - and Raman spectra of two layered bismuth-tellurohalides BiTeBr and BiTeCl at 300 K and 5 K, for light polarized in the a-b planes. Despite different space groups, the optical properties of the two compounds are very similar. Both materials are doped semiconductors, with the absorption edge above the optical gap which is lower in BiTeBr (0.62 eV) than in BiTeCl (0.77 eV). The same Rashba splitting is observed in the two materials. A non-Drude free carrier contribution in the optical conductivity, as well as three Raman and two infrared phonon modes, are observed in each compound. There is a dramatic difference in the highest infrared phonon intensity for the two compounds, and a difference in the doping levels. Aspects of the strong electron-phonon interaction are identified. Several interband transitions are assigned, among them the low-lying absorption $\beta$ which has the same value 0.25 eV in both compounds, and is caused by the Rashba spin splitting of the conduction band. An additional weak transition is found in BiTeCl, caused by the lower crystal symmetry.

Accepted in PRB

References in corpus (12)

• Kramers-Kronig constrained variational analysis of optical spectra
• Emergence of non-centrosymmetric topological insulating phase in BiTeI under pressure
• Ideal two-dimensional electron systems with a giant Rashba-type spin splitting in real materials: surfaces of bismuth tellurohalides
• Giant ambipolar Rashba effect in a semiconductor: BiTeI
• Strongly spin-orbit coupled two-dimensional electron gas emerging near the surface of polar semiconductors
• Signatures of a Pressure-Induced Topological Quantum Phase Transition in BiTeI
• Surface and bulk Fermiology and band dispersion in non-centrosymmetric BiTeI
• Infrared spectroscopic study of phonons coupled to charge excitations in FeSi
• Infrared and Raman spectroscopy measurements of a transition in the crystal structure and a closing of the energy gap of BiTeI under pressure
• Giant magneto-optical response in non-magnetic semiconductor BiTeI driven by bulk Rashba spin splitting
• Many-body effects on the Rashba-type spin splitting in bulk bismuth tellurohalides
• Atomic and Electronic Structure of a Rashba $p$-$n$ Junction at the BiTeI Surface

Cited by in corpus (12)

• Electrically Controlled Spin Injection from Giant Rashba Spin-Orbit Conductor BiTeBr
• Pressure-induced topological phase transition in polar semiconductor BiTeBr
• Temperature dependence of the bulk Rashba splitting in the bismuth tellurohalides
• Superconductivity in Dense Rashba Semiconductor BiTeCl
• Ab initio electronic structure and optical conductivity of bismuth tellurohalides
• Unusual Shubnikov-de Haas oscillations in BiTeCl
• BiTeCl and BiTeBr: a comparative high-pressure optical study
• Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor
• In situ tuning of symmetry-breaking induced non-reciprocity in giant-Rashba semiconductor BiTeBr
• Wavevector-dependent optical properties from wavevector-independent proper conductivity tensor
• Growth of Large Crystals of Janus Phase RhSeCl Using Self-Selecting Vapour Growth
• Bismuth and Antimony Based Oxyhalides and Chalcohalides as Potential Optoelectronic Materials