Figure 1

The $pT$ phase diagram of 1$T$–${\mathrm{TaS}}_2$. Blue square markers represent data from electrical resistivity measurements (Ref. 15) and red circle markers the transition temperatures found by XRD in this study (C: commensurate, NC: nearly commensurate, IC: incommensurate, SC: superconducting). The C phase is characterized by a large hysteresis illustrated by the transparent reddish region.Reuse & Permissions

Figure 2

Reciprocal space maps of the XRD intensity for the C phase (a), the NC phase (b), and the high-pressure IC phase (c). In (a) the Bragg reflections are indicated by the Miller indices $\left(hkl\right),$ and the reciprocal lattice vectors ${\mathbf{a}}^{*}$, ${\mathbf{b}}^{*}$ of the hexagonal plane are shown by black arrows. A magnified region in reciprocal space is displayed in the insets, where the threefold splitting of the satellite reflections in the NC phase and the high-pressure IC phase can be clearly observed. (d) and (e) The satellite peak positions in the NC phase as a function of $p$ at 300 K and 15 K, respectively. In addition, (d) illustrates the geometric relation between first and third order satellite peaks, whereas ${\mathbf{q}}_1={\mathbf{q}}_{\mathrm{NC}}-{\mathbf{q}}_{\mathrm{C}}$ and rotating ${\mathbf{q}}_1$ by ${120}^{\circ }$ and ${240}^{\circ }$ yields ${\mathbf{q}}_2$ and ${\mathbf{q}}_3$, respectively. At both 300 K and 15 K, the modulation wave vector clearly shifts towards the IC position with increasing $p$. (e) Includes data taken in the SC region of the phase diagram at 45 kbar and 3.4 K. (f) $k$ scans through the third-order satellite peak [along red arrow in inset of (b)] versus $p$ at $T=300$ K, illustrating the clear $p$ dependence of the peak position and intensity. The solid lines in (f) represent fitted pseudo-Voigt profiles.Reuse & Permissions

Figure 3

In-plane components of the modulation wave vector as a function of pressure. Red closed circle markers and blue square markers represent the room- and low-temperature measurement, respectively. At room temperature the NC-IC transition occurs at $P\approx 20$ kbar (red dashed line). For low temperatures we observed the C-NC-transition and the NC-IC-transition at about 40 kbar and 70 kbar, respectively (blue dashed lines). Within the NC phase the $\mathbf{q}$ vector shifts towards ${\mathbf{q}}_{\mathrm{IC}}$. Solid lines are guides to the eye.Reuse & Permissions

Figure 4

(a) Calculated C-domain distance as a function of pressure using Eq. (1). (b) Intensity ratio between the first- and third-order satellite reflection. (c) Overall intensity of the first-order satellite reflection. Dotted lines are guides to the eye. (d) and (e) Two possible scenarios of pressure-induced C-domain shrinking in real space. The reddish hexagons refer to C-CDW domains and the gray areas represent the discommensurations. (d) The distance between C-CDW domains remains constant and the domain boundaries smear out. In (e) the C-domain distance shrinks and the domain boundaries remain sharp.Reuse & Permissions