Thermoelectric probe for Fermi surface topology in the three-dimensional Rashba semiconductor BiTeI

Ideue, Toshiya; Ye, L.; Checkelsky, Joseph; Murakawa, H.; Tokura, Y.

doi:10.1103/physrevb.92.115144

Cited by 16 publications

(14 citation statements)

References 23 publications

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“…As shown in Supplementary Fig. 4, this approach yields results consistent with the experimental data 5,[33][34][35] . All electrical transport properties presented here are calculated with the same deformation potential and Young's modulus, without the use of any undetermined parameter.…”

Section: Rashba Engineering For Optimizing Power Factorssupporting

confidence: 82%

“…The Rashba effect plays a critical role in controlling the electronic structure and therefore the functional properties of semiconductors, including topological insulators and thermoelectrics [1][2][3][4][5][6][7] . The Bychkov-Rashba form of the spin-orbit coupling (SOC) perturbation Hamiltonian, H R = α R (σ × k)•z 8 , is used to describe the strength of the Rashba effect, where α R is the Rashba parameter (α R ∝ E z , E z is the electric field 9 ), σ the Pauli spin matrices, k the momentum, and z the direction of the electric field.…”

Section: Introductionmentioning

confidence: 99%

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Defect-mediated Rashba engineering for optimizing electrical transport in thermoelectric BiTeI

et al. 2020

npj Comput Mater

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The Rashba effect plays a vital role in electronic structures and related functional properties. The strength of the Rashba effect can be measured by the Rashba parameter α R ; it is desirable to manipulate α R to control the functional properties. The current work illustrates how α R can be systematically tuned by doping, taking BiTeI as an example. A five-point-spin-texture method is proposed to efficiently screen doped BiTeI systems with the Rashba effect. Our results show that α R in doped BiTeI can be manipulated within the range of 0-4.05 eV Å by doping different elements. The dopants change α R by affecting both the spin-orbit coupling strength and band gap. Some dopants with low atomic masses give rise to unexpected and sizable α R , mainly due to the local strains. The calculated electrical transport properties reveal an optimal α R range of 2.75-3.55 eV Å for maximizing the thermoelectric power factors. α R thus serves as an effective indicator for high-throughput screening of proper dopants and subsequently reveals a few promising Rashba thermoelectrics. This work demonstrates the feasibility of defect-mediated Rashba engineering for optimizing the thermoelectric properties, as well as for manipulating other spin-related functional properties.

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Section: Rashba Engineering For Optimizing Power Factorssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Defect-mediated Rashba engineering for optimizing electrical transport in thermoelectric BiTeI

et al. 2020

npj Comput Mater

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“…For example, the Zeeman field arising from the magnetic moments can induce a noticeable gap at the CP, which may in turn enable formation of Majorana states . Thermoelectric properties (Seebeck and Nernst effects) in BiTe X are also interesting and of practical use …”

Section: Discussion and Outlookmentioning

confidence: 99%

Bulk Rashba Semiconductors and Related Quantum Phenomena

Bahramy

Ogawa

2017

Advanced Materials

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zone (BZ) unless it is protected by a special crystalline symmetry. If the breaking of IS is such that the electrons feel a net gradient of potential normal to their momentum direction, the SOI results in a situation where every electron's spin is locked perpendicular to its momentum (see Figure 1). This phenomenon is called the Rashba effect [2,3] and is known to be responsible for many novel quantum phenomena such as spin Hall and Edelstein effects, [4,5] spin galvanic effect, [6] magnetoelectric effect, [7] and non-centrosymmetric superconductivity. [8] Although the Rashba effect has been known for more than sixty years, it has been mainly sought for in two-dimensional (2D) electronic systems, such as the semiconductor heterostructures [9] and the surface/interface of noble and heavy metals. [10] This is because the general rationale has been that the bulk systems can not exhibit a sizable Rashba spin splitting (RSS) due to the internal constraints such as the electric dipole screening. The recent angle-resolved photoemission spectroscopy (ARPES) study by Ishizaka et al. has, however, proven that this picture is not always true. [11] Their ARPES data, backed by the first principles calculations, [12] have revealed that in the polar semiconductor BiTeI, the bulk states exhibit an extremely large RSS. In fact, the RSS observed in bulk BiTeI has been shown [11] to exceed the largest RSS realized in a 2D system. [10] Further ARPES experiments [13][14][15][16][17] and ab initio calculations [18] have unveiled the similar effect in the other bismuth tellurohallides (BiTeBr and BiTeCl) and even in some ferroelectric semiconductors such as GeTe. [19,20] In all these systems, it turns out that the bulk RSS originates from an anomalous ordering of the conduction and/or valence bands combined with the strong SOI and narrowness of the band gap. [12] The bulk RSS has also been shown to lead to a variety of quantum effects in BiTeX (X = Cl, Br and I) compounds such as unique optical transitions, [21] strong magnetooptical responses, [22] a divergent orbital dia-/para-magnetism, [23] zero-bias magneto-and galvanic photocurrent [24,25] and a nontrivial Berry's phase. [26] Moreover, it has been theoretically proposed [27] and indications have been experimentally reported [28,29] that these systems may turn into a topological insulator under the application of a hydrostatic pressure. Together, these effects indicate that bulk RSS provide a new route to manipulate the spin degree of freedom of electrons, and BiTeX, as Bithmuth tellurohalides BiTeX (X = Cl, Br and I) are model examples of bulk Rashba semiconductors, exhibiting a giant Rashba-type spin splitting among their both valence and conduction bands. Extensive spectroscopic and transport experiments combined with the state-of-the-art first-principles calculations have revealed many unique quantum phenomena emerging from the bulk Rashba effect in these systems. The novel features such as the exotic inter-and intra-band optical transitions, enhanced magneto-optical response...

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“…1a). The resultant Rashba-type spin splitting of the electronic bands has been confirmed by angle-resolved photoemission spectroscopy (ARPES) 15,16 and the transport signatures of the split Fermi surface have been reported by quantum oscillations in resistance 19 or thermoelectric coefficients 20 . However, characteristic magneto-transport reflecting the spin polarization in the electronic band or polarity of the crystal has been elusive, except for photocurrent experiments on BiTeBr 21 .…”

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confidence: 85%

Bulk rectification effect in a polar semiconductor

et al. 2017

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Noncentrosymmetric conductors are an interesting material platform, with rich spintronic functionalities 1,2 and exotic superconducting properties 3,4 typically produced in polar systems with Rashba-type spin-orbit interactions 5 . Polar conductors should also exhibit inherent nonreciprocal transport [6][7][8] , in which the rightward and leftward currents di er from each other. But such a rectification is di cult to achieve in bulk materials because, unlike the translationally asymmetric p-n junctions, bulk materials are translationally symmetric, making this phenomenon highly nontrivial. Here we report a bulk rectification e ect in a three-dimensional Rashba-type polar semiconductor BiTeBr. Experimentally observed nonreciprocal electric signals are quantitatively explained by theoretical calculations based on the Boltzmann equation considering the giant Rashba spin-orbit coupling. The present result o ers a microscopic understanding of the bulk rectification e ect intrinsic to polar conductors as well as a simple electrical means to estimate the spin-orbit parameter in a variety of noncentrosymmetric systems.The effect of the lattice symmetry on the electronic states is a fundamental issue in condensed matter physics. In particular, broken inversion symmetry in the crystal structure generally causes spin band splitting which modifies the electronic ground state, affecting transport properties represented by the superconductivity in noncentrosymmetric systems 3,4 or spin-related transport in nonmagnetic materials 1,2 . Among them, Rashba-5 and Dresselhaus 9 -type spin-orbit interactions are two well-known textbook models which have succeeded in explaining a variety of exotic phenomena in systems without inversion symmetry.Although the Rashba effect has been conventionally studied at surfaces or interfaces [10][11][12][13][14] , the recent discovery of three-dimensional (3D) materials which host a large Rashba-type band splitting [15][16][17][18] pave the way towards exploring novel transport originating from the 3D chiral spin-texture of the electronic band. BiTeX (X = I, Br) is one such bulk polar semiconductor, in which Bi, Te and X layers are stacked alternately so that the mirror symmetry along the c axis is broken (Fig. 1a). The resultant Rashba-type spin splitting of the electronic bands has been confirmed by angle-resolved photoemission spectroscopy (ARPES) 15,16 and the transport signatures of the split Fermi surface have been reported by quantum oscillations in resistance 19 or thermoelectric coefficients 20 . However, characteristic magneto-transport reflecting the spin polarization in the electronic band or polarity of the crystal has been elusive, except for photocurrent experiments on BiTeBr 21 . One of the manifestations of lattice symmetry breaking in electric transport is the rectification effect. In the presence of an in-plane magnetic field, the Rashba-type spin band splitting is modulated to become asymmetric along a direction perpendicular to both the polar axis and the magnetic field (Fig. ...

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Thermoelectric probe for Fermi surface topology in the three-dimensional Rashba semiconductor BiTeI

Cited by 16 publications

References 23 publications

Defect-mediated Rashba engineering for optimizing electrical transport in thermoelectric BiTeI

Defect-mediated Rashba engineering for optimizing electrical transport in thermoelectric BiTeI

Bulk Rashba Semiconductors and Related Quantum Phenomena

Bulk rectification effect in a polar semiconductor

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